diff --git a/code/mission/missioncampaign.cpp b/code/mission/missioncampaign.cpp
index f4b853d5b09..a271bca3e46 100644
--- a/code/mission/missioncampaign.cpp
+++ b/code/mission/missioncampaign.cpp
@@ -82,10 +82,9 @@ const char *campaign_types[MAX_CAMPAIGN_TYPES] =
 //XSTR:ON
 };
 
-// modules local variables to deal with getting new ships/weapons available to the player
-int Num_granted_ships, Num_granted_weapons;		// per mission counts of new ships and weapons
-int Granted_ships[MAX_SHIP_CLASSES];
-int Granted_weapons[MAX_WEAPON_TYPES];
+// module-local sets of new ships/weapons granted to the player during the current mission
+static SCP_set<int> Granted_ships;
+static SCP_set<int> Granted_weapons;
 
 // variables to control the UI stuff for loading campaigns
 LOCAL UI_WINDOW Campaign_window;
@@ -397,16 +396,16 @@ void mission_campaign_get_sw_info()
 		SCP_vector<int> ship_list;
 		stuff_int_list(ship_list, ParseLookupType::SHIP_INFO_TYPE);
 
-		// now set the array elements stating which ships we are allowed
+		// now note which ships we are allowed
 		for (int idx : ship_list) {
 			if (Ship_info[idx].flags[Ship::Info_Flags::Player_ship])
-				Campaign.ships_allowed[idx] = 1;
+				Campaign.ships_allowed.insert(idx);
 		}
 	} else {
 		// set allowable ships to the SIF_PLAYER_SHIPs
 		for (auto it = Ship_info.cbegin(); it != Ship_info.cend(); ++it) {
 			if (it->flags[Ship::Info_Flags::Player_ship])
-				Campaign.ships_allowed[std::distance(Ship_info.cbegin(), it)] = 1;
+				Campaign.ships_allowed.insert(static_cast<int>(std::distance(Ship_info.cbegin(), it)));
 		}
 	}
 
@@ -414,16 +413,16 @@ void mission_campaign_get_sw_info()
 		SCP_vector<int> weapon_list;
 		stuff_int_list(weapon_list, ParseLookupType::WEAPON_POOL_TYPE);
 
-		// now set the array elements stating which weapons we are allowed
+		// now note which weapons we are allowed
 		for (int idx : weapon_list) {
 			if (Weapon_info[idx].wi_flags[Weapon::Info_Flags::Player_allowed])
-				Campaign.weapons_allowed[idx] = 1;
+				Campaign.weapons_allowed.insert(idx);
 		}
 	} else {
 		// set allowable weapons to the player-allowed ones
 		for (auto it = Weapon_info.cbegin(); it != Weapon_info.cend(); ++it) {
 			if (it->wi_flags[Weapon::Info_Flags::Player_allowed])
-				Campaign.weapons_allowed[std::distance(Weapon_info.cbegin(), it)] = 1;
+				Campaign.weapons_allowed.insert(static_cast<int>(std::distance(Weapon_info.cbegin(), it)));
 		}
 	}
 }
@@ -837,9 +836,9 @@ int mission_campaign_next_mission()
 		Campaign.loop_enabled = 0;
 	}
 
-	// reset the number of persistent ships and weapons for the next campaign mission
-	Num_granted_ships = 0;
-	Num_granted_weapons = 0;
+	// reset the persistent ships and weapons for the next campaign mission
+	Granted_ships.clear();
+	Granted_weapons.clear();
 	return 0;
 }
 
@@ -876,8 +875,8 @@ int mission_campaign_previous_mission()
 	Player->stats.assign( Campaign.missions[Campaign.current_mission].stats );
 
 	strcpy_s( Game_current_mission_filename, Campaign.missions[Campaign.current_mission].name );
-	Num_granted_ships = 0;
-	Num_granted_weapons = 0;
+	Granted_ships.clear();
+	Granted_weapons.clear();
 
 	return 1;
 }
@@ -1119,7 +1118,7 @@ void mission_campaign_store_goals_and_events_and_variables(bool store_red_alert_
  */
 void mission_campaign_mission_over(bool do_next_mission)
 {
-	int mission_num, i;
+	int mission_num;
 	cmission *mission_obj;
 
 	// I don't think that we should have a record for these -- maybe we might??????  If we do,
@@ -1133,13 +1132,8 @@ void mission_campaign_mission_over(bool do_next_mission)
 	mission_obj = &Campaign.missions[mission_num];
 
 	// determine if any ships/weapons were granted this mission
-	for ( i=0; i<Num_granted_ships; i++ ){
-		Campaign.ships_allowed[Granted_ships[i]] = 1;
-	}
-
-	for ( i=0; i<Num_granted_weapons; i++ ){
-		Campaign.weapons_allowed[Granted_weapons[i]] = 1;	
-	}
+	Campaign.ships_allowed.insert(Granted_ships.begin(), Granted_ships.end());
+	Campaign.weapons_allowed.insert(Granted_weapons.begin(), Granted_weapons.end());
 
 	// update campaign.mission stats (used to allow backout inRedAlert)
 	// .. but we don't do this if we are inside of the prev/current loop hack
@@ -1269,8 +1263,8 @@ void mission_campaign_clear()
 	Campaign.loop_reentry = 0;
 	Campaign.realign_required = 0;
 	Campaign.num_players = 0;
-	Campaign.ships_allowed.assign(ship_info_size(), 0);
-	Campaign.weapons_allowed.assign(weapon_info_size(), 0);
+	Campaign.ships_allowed.clear();
+	Campaign.weapons_allowed.clear();
 	Campaign.persistent_variables.clear(); 
 	Campaign.red_alert_variables.clear();
 	Campaign.persistent_containers.clear();
@@ -1541,13 +1535,9 @@ void mission_campaign_save_persistent( int type, int sindex )
 	// based on the type of information, save it off for possible saving into the campsign
 	// savefile when the mission is over
 	if ( type == CAMPAIGN_PERSISTENT_SHIP ) {
-		Assert( Num_granted_ships < MAX_SHIP_CLASSES );
-		Granted_ships[Num_granted_ships] = sindex;
-		Num_granted_ships++;
+		Granted_ships.insert(sindex);
 	} else if ( type == CAMPAIGN_PERSISTENT_WEAPON ) {
-		Assert( Num_granted_weapons < MAX_WEAPON_TYPES );
-		Granted_weapons[Num_granted_weapons] = sindex;
-		Num_granted_weapons++;
+		Granted_weapons.insert(sindex);
 	} else
 		Int3();
 }
@@ -1825,12 +1815,11 @@ bool mission_campaign_jump_to_mission(const char* filename, bool no_skip, bool p
 		return false;
 	} else {
 		if (!preserve_loadout) {
-			for (auto it = Ship_info.begin(); it != Ship_info.end(); it++) {
-				i = static_cast<int>(std::distance(Ship_info.begin(), it));
-				Campaign.ships_allowed[i] = 1;
+			for (i = 0; i < ship_info_size(); i++) {
+				Campaign.ships_allowed.insert(i);
 			}
 			for (i = 0; i < weapon_info_size(); i++) {
-				Campaign.weapons_allowed[i] = 1;
+				Campaign.weapons_allowed.insert(i);
 			}
 		}
 
diff --git a/code/mission/missioncampaign.h b/code/mission/missioncampaign.h
index 069c2303094..41d7042023e 100644
--- a/code/mission/missioncampaign.h
+++ b/code/mission/missioncampaign.h
@@ -129,8 +129,8 @@ class campaign
 	int		loop_reentry;							// mission number to return to after loop is finished
 	int		realign_required;						// are any missions missing alignment info? (Fred)
 	int		num_players;							// valid in multiplayer campaigns -- number of players campaign supports.
-	SCP_vector<ubyte>	ships_allowed;					// which ships the player can use
-	SCP_vector<ubyte>	weapons_allowed;				// which weapons the player can use
+	SCP_set<int>	ships_allowed;						// class indices of ships the player can use; absent = not allowed
+	SCP_set<int>	weapons_allowed;					// class indices of weapons the player can use; absent = not allowed
 	cmission	missions[MAX_CAMPAIGN_MISSIONS];	// decription of the missions
 	SCP_vector<sexp_variable> persistent_variables;		// These variables will be saved at the end of a mission
 	SCP_vector<sexp_variable> red_alert_variables;		// state of the variables in the previous mission of a Red Alert scenario.
diff --git a/code/mission/missionparse.cpp b/code/mission/missionparse.cpp
index b5090b26fd0..487d5fba92a 100644
--- a/code/mission/missionparse.cpp
+++ b/code/mission/missionparse.cpp
@@ -1251,16 +1251,15 @@ void parse_player_info2(mission *pm)
 
 		// check ship class loadout entries
 		for (auto &sc : list) {
+			if (!Ship_info.in_bounds(sc.index))
+				continue;
+
 			// in a campaign, see if the player is allowed the ships or not.  Remove them from the
 			// pool if they are not allowed
 			if (Game_mode & GM_CAMPAIGN_MODE || (MULTIPLAYER_CLIENT)) {
-				if ( !Campaign.ships_allowed[sc.index] )
+				if ( !Campaign.ships_allowed.contains(sc.index) )
 					continue;
 			}
-			if (sc.index < 0 || sc.index >= ship_info_size())
-				continue;
-
-			ptr->ship_list[num_choices] = sc.index;
 
 			// if the list isn't set by a variable leave the variable name empty
 			if (sc.index_sexp_var == NOT_SET_BY_SEXP_VARIABLE) {
@@ -1270,6 +1269,7 @@ void parse_player_info2(mission *pm)
 				strcpy_s(ptr->ship_list_variables[num_choices], Sexp_variables[sc.index_sexp_var].variable_name);
 			}
 
+			ptr->ship_list[num_choices] = sc.index;
 			ptr->ship_count[num_choices] = sc.count;
 			ptr->loadout_total += sc.count;
 
@@ -1297,9 +1297,9 @@ void parse_player_info2(mission *pm)
 			// see if the player's default ship is an allowable ship (campaign only). If not, then what
 			// do we do?  choose the first allowable one?
 			if (Game_mode & GM_CAMPAIGN_MODE || (MULTIPLAYER_CLIENT)) {
-				if ( !(Campaign.ships_allowed[ptr->default_ship]) ) {
+				if ( !Campaign.ships_allowed.contains(ptr->default_ship) ) {
 					for (i = 0; i < ship_info_size(); i++ ) {
-						if ( Campaign.ships_allowed[i] ) {
+						if ( Campaign.ships_allowed.contains(i) ) {
 							ptr->default_ship = i;
 							break;
 						}
@@ -1327,15 +1327,16 @@ void parse_player_info2(mission *pm)
 
 		// check weapon class loadout entries
 		for (auto &wc : list2) {
+			if (!Weapon_info.in_bounds(wc.index))
+				continue;
+
 			// in a campaign, see if the player is allowed the weapons or not.  Remove them from the
 			// pool if they are not allowed
 			if (Game_mode & GM_CAMPAIGN_MODE || (MULTIPLAYER_CLIENT)) {
-				if ( !Campaign.weapons_allowed[wc.index] ) {
+				if ( !Campaign.weapons_allowed.contains(wc.index) ) {
 					continue;
 				}
 			}
-			if (wc.index < 0 || wc.index >= weapon_info_size())
-				continue;
 
 			// always allow the pool to be added in FRED, it is a verbal warning
 			// to let the mission dev know about the problem
@@ -1346,6 +1347,7 @@ void parse_player_info2(mission *pm)
 
 			ptr->weaponry_pool[num_choices] = wc.index; 
 			ptr->weaponry_count[num_choices] = wc.count;
+
 			if (pm->support_ships.rearm_pool_from_loadout) {
 				if (Weapon_info[wc.index].disallow_rearm) {
 					pm->support_ships.rearm_weapon_pool[nt][wc.index] = 0;
diff --git a/code/missioneditor/campaignsave.cpp b/code/missioneditor/campaignsave.cpp
index 6ffec6635bb..a36b02e05b2 100644
--- a/code/missioneditor/campaignsave.cpp
+++ b/code/missioneditor/campaignsave.cpp
@@ -88,9 +88,8 @@ int Fred_campaign_save::save_campaign_file(const char* pathname, const SCP_vecto
 		fout("\n\n+Starting Ships:");
 	}
 	fout(" (");
-	for (int i = 0; i < ship_info_size(); i++) {
-		if (Campaign.ships_allowed[i])
-			fout(" \"%s\"", Ship_info[i].name);
+	for (int ship_class : Campaign.ships_allowed) {
+		fout(" \"%s\"", Ship_info[ship_class].name);
 	}
 	fout(" )");
 
@@ -100,9 +99,8 @@ int Fred_campaign_save::save_campaign_file(const char* pathname, const SCP_vecto
 		fout("\n\n+Starting Weapons:");
 	}
 	fout(" (");
-	for (int i = 0; i < weapon_info_size(); i++) {
-		if (Campaign.weapons_allowed[i])
-			fout(" \"%s\"", Weapon_info[i].name);
+	for (int weapon_class : Campaign.weapons_allowed) {
+		fout(" \"%s\"", Weapon_info[weapon_class].name);
 	}
 	fout(" )");
 
diff --git a/code/network/multi_campaign.cpp b/code/network/multi_campaign.cpp
index 5c5454adf51..2f89aa7303d 100644
--- a/code/network/multi_campaign.cpp
+++ b/code/network/multi_campaign.cpp
@@ -270,25 +270,25 @@ void multi_campaign_process_update(ubyte *data, header *hinfo)
 		if(!val){
 			// all ships
 			for(idx = 0; idx < ship_info_size(); idx++) {
-				Campaign.ships_allowed[idx] = 1;
+				Campaign.ships_allowed.insert(idx);
 			}
 
 			// all weapons
 			for(idx = 0; idx < weapon_info_size(); idx++) {
-				Campaign.weapons_allowed[idx] = 1;
+				Campaign.weapons_allowed.insert(idx);
 			}
 		} else {
-			// clear the ships and weapons allowed arrays
-			Campaign.ships_allowed.assign(ship_info_size(), 0);
-			Campaign.weapons_allowed.assign(weapon_info_size(), 0);
+			// clear the ships and weapons allowed sets
+			Campaign.ships_allowed.clear();
+			Campaign.weapons_allowed.clear();
 
 			// get all ship classes
 			GET_USHORT(spool_size);
 			for(idx=0;idx<spool_size;idx++){
 				GET_USHORT(s_val);
 
-				if (Campaign.ships_allowed.in_bounds(s_val)) {
-					Campaign.ships_allowed[s_val] = 1;
+				if (Ship_info.in_bounds(s_val)) {
+					Campaign.ships_allowed.insert(s_val);
 				}
 			}
 
@@ -297,8 +297,8 @@ void multi_campaign_process_update(ubyte *data, header *hinfo)
 			for(idx=0;idx<wpool_size;idx++){
 				GET_USHORT(s_val);
 
-				if (Campaign.weapons_allowed.in_bounds(s_val)) {
-					Campaign.weapons_allowed[s_val] = 1;
+				if (Weapon_info.in_bounds(s_val)) {
+					Campaign.weapons_allowed.insert(s_val);
 				}
 			}
 		}
@@ -449,7 +449,6 @@ void multi_campaign_send_debrief_info()
 void multi_campaign_send_pool_status()
 {
 	ubyte data[MAX_PACKET_SIZE],val;
-	int idx;
 	int spool_size;
 	int wpool_size;
 	int packet_size = 0;
@@ -471,21 +470,8 @@ void multi_campaign_send_pool_status()
 		val = 0x1;
 		ADD_DATA(val);
 
-		// determine how many ship types we're going to add
-		spool_size = 0;
-		for(idx = 0; idx < ship_info_size(); idx++) {
-			if(Campaign.ships_allowed[idx]){
-				spool_size++;
-			}
-		}
-		
-		// determine how many weapon types we're going to add
-		wpool_size = 0;
-		for(idx = 0; idx < weapon_info_size(); idx++){
-			if(Campaign.weapons_allowed[idx]){
-				wpool_size++;
-			}
-		}
+		spool_size = sz2i(Campaign.ships_allowed.size());
+		wpool_size = sz2i(Campaign.weapons_allowed.size());
 
 #ifndef NDEBUG
 		// make sure it'll all fit into this packet
@@ -495,20 +481,16 @@ void multi_campaign_send_pool_status()
 				  "Allowed ship/weapon pool is too large!");
 #endif
 
-		// add all ship types
+		// add all ship types (SCP_set iterates in ascending class order)
 		ADD_USHORT(static_cast<ushort>(spool_size));
-		for(idx = 0; idx < ship_info_size(); idx++) {
-			if(Campaign.ships_allowed[idx]){
-				ADD_USHORT(static_cast<ushort>(idx));
-			}
+		for(int ship_class : Campaign.ships_allowed) {
+			ADD_USHORT(static_cast<ushort>(ship_class));
 		}
 
 		// add all weapon types
 		ADD_USHORT(static_cast<ushort>(wpool_size));
-		for(idx = 0; idx < weapon_info_size(); idx++){
-			if(Campaign.weapons_allowed[idx]){
-				ADD_USHORT(static_cast<ushort>(idx));
-			}
+		for(int weapon_class : Campaign.weapons_allowed) {
+			ADD_USHORT(static_cast<ushort>(weapon_class));
 		}
 	}
 
diff --git a/code/pilotfile/csg.cpp b/code/pilotfile/csg.cpp
index 6f8a0f8af5b..9efd6b565c6 100644
--- a/code/pilotfile/csg.cpp
+++ b/code/pilotfile/csg.cpp
@@ -163,7 +163,7 @@ void pilotfile::csg_read_info()
 
 		if (allowed) {
 			if (ship_list[idx].index >= 0) {
-				Campaign.ships_allowed[ship_list[idx].index] = 1;
+				Campaign.ships_allowed.insert(ship_list[idx].index);
 			} else {
 				mprintf(("Found invalid ship \"%s\" in campaign save file. Skipping...\n", ship_list[idx].name.c_str()));
 			}
@@ -177,7 +177,7 @@ void pilotfile::csg_read_info()
 
 		if (allowed) {
 			if (weapon_list[idx].index >= 0) {
-				Campaign.weapons_allowed[weapon_list[idx].index] = 1;
+				Campaign.weapons_allowed.insert(weapon_list[idx].index);
 			} else {
 				mprintf(("Found invalid weapon \"%s\" in campaign save file. Skipping...\n",
 				         weapon_list[idx].name.c_str()));
@@ -247,12 +247,12 @@ void pilotfile::csg_write_info()
 
 	// allowed ships
 	for (idx = 0; idx < ship_info_size(); idx++) {
-		cfwrite_ubyte(Campaign.ships_allowed[idx], cfp);
+		cfwrite_ubyte(Campaign.ships_allowed.contains(idx) ? 1 : 0, cfp);
 	}
 
 	// allowed weapons
 	for (idx = 0; idx < weapon_info_size(); idx++) {
-		cfwrite_ubyte(Campaign.weapons_allowed[idx], cfp);
+		cfwrite_ubyte(Campaign.weapons_allowed.contains(idx) ? 1 : 0, cfp);
 	}
 
 	// single/campaign squad name & image
@@ -1610,8 +1610,8 @@ void pilotfile::csg_reset_data(bool reset_ships_and_weapons)
 
 	// zero out allowed ships/weapons
 	if (reset_ships_and_weapons) {
-		Campaign.ships_allowed.assign(ship_info_size(), 0);
-		Campaign.weapons_allowed.assign(weapon_info_size(), 0);
+		Campaign.ships_allowed.clear();
+		Campaign.weapons_allowed.clear();
 	}
 
 	// reset campaign status
diff --git a/code/scripting/api/objs/shipclass.cpp b/code/scripting/api/objs/shipclass.cpp
index b1482807e7d..51dddcba68c 100644
--- a/code/scripting/api/objs/shipclass.cpp
+++ b/code/scripting/api/objs/shipclass.cpp
@@ -962,10 +962,14 @@ ADE_VIRTVAR(AllowedInCampaign, l_Shipclass, "boolean", "Gets or sets whether thi
 		return ade_set_error(L, "b", false);
 
 	if (ADE_SETTING_VAR) {
-		Campaign.ships_allowed[idx] = new_value;
+		if (new_value) {
+			Campaign.ships_allowed.insert(idx);
+		} else {
+			Campaign.ships_allowed.erase(idx);
+		}
 	}
 
-	return Campaign.ships_allowed[idx] ? ADE_RETURN_TRUE : ADE_RETURN_FALSE;
+	return Campaign.ships_allowed.contains(idx) ? ADE_RETURN_TRUE : ADE_RETURN_FALSE;
 }
 
 ADE_VIRTVAR(PowerOutput, l_Shipclass, "number", "Gets or sets a ship class' power output", "number", "The ship class' current power output")
diff --git a/code/scripting/api/objs/weaponclass.cpp b/code/scripting/api/objs/weaponclass.cpp
index 86a69c0eb18..d4a159c5e8c 100644
--- a/code/scripting/api/objs/weaponclass.cpp
+++ b/code/scripting/api/objs/weaponclass.cpp
@@ -828,10 +828,14 @@ ADE_VIRTVAR(AllowedInCampaign, l_Weaponclass, "boolean", "Gets or sets whether t
 		return ade_set_error(L, "b", false);
 
 	if (ADE_SETTING_VAR) {
-		Campaign.weapons_allowed[idx] = new_value;
+		if (new_value) {
+			Campaign.weapons_allowed.insert(idx);
+		} else {
+			Campaign.weapons_allowed.erase(idx);
+		}
 	}
 
-	return Campaign.weapons_allowed[idx] ? ADE_RETURN_TRUE : ADE_RETURN_FALSE;
+	return Campaign.weapons_allowed.contains(idx) ? ADE_RETURN_TRUE : ADE_RETURN_FALSE;
 }
 
 ADE_VIRTVAR(CargoSize, l_Weaponclass, "number", "The cargo size of this weapon class", "number", "The new cargo size or -1 on error")
diff --git a/fred2/initialships.cpp b/fred2/initialships.cpp
index 773449291a1..b3aa4db5841 100644
--- a/fred2/initialships.cpp
+++ b/fred2/initialships.cpp
@@ -67,9 +67,9 @@ BOOL InitialShips::OnInitDialog()
 	if ( m_initial_items == INITIAL_SHIPS ) {
         for (auto it = Ship_info.cbegin(); it != Ship_info.cend(); ++it) {
             if (it->flags[Ship::Info_Flags::Player_ship]) {
-                auto i = std::distance(Ship_info.cbegin(), it);
+                int i = static_cast<int>(std::distance(Ship_info.cbegin(), it));
                 m_initial_list.AddString(it->name);
-                if (Campaign.ships_allowed[i]) {
+                if (Campaign.ships_allowed.contains(i)) {
                     m_initial_list.SetCheck(m_list_count, 1);
                 }
                 else if ((strlen(Campaign.filename) == 0) && strstr(it->name, "Myrmidon")) { //-V805
@@ -104,7 +104,7 @@ BOOL InitialShips::OnInitDialog()
 			if ( allowed_weapons[i] ) {
 				m_initial_list.AddString( Weapon_info[i].name );
 				int add_weapon = 0;
-				if ( Campaign.weapons_allowed[i] ) {
+				if ( Campaign.weapons_allowed.contains(i) ) {
 					add_weapon = 1;
 				} else if ( strlen(Campaign.filename) == 0 ) { //-V805
 					if ( strstr(Weapon_info[i].name, "Subach")) {
@@ -142,25 +142,24 @@ void InitialShips::OnOK()
 {
 	int i;
 
-	// zero out whichever array we are setting
+	// zero out whichever set we are setting
 	if ( m_initial_items == INITIAL_SHIPS ) {
-		Campaign.ships_allowed.assign(ship_info_size(), 0);
+		Campaign.ships_allowed.clear();
 	} else if ( m_initial_items == INITIAL_WEAPONS ) {
-		Campaign.weapons_allowed.assign(weapon_info_size(), 0);
+		Campaign.weapons_allowed.clear();
 	}
 
 	for ( i = 0; i < m_list_count; i++ ) {
 		if ( m_initial_list.GetCheck(i) ) {
 			// this item is checked.  Get the index into either the ship info array or the weapons
 			// array
-			auto index = m_initial_list.GetItemData(i);
+			int index = static_cast<int>(m_initial_list.GetItemData(i));
 			if ( m_initial_items == INITIAL_SHIPS ) {
-				Campaign.ships_allowed[index] = 1;
+				Campaign.ships_allowed.insert(index);
 			} else if ( m_initial_items == INITIAL_WEAPONS ) {
-				Campaign.weapons_allowed[index] = 1;
+				Campaign.weapons_allowed.insert(index);
 			} else
 				Int3();
-			
 		}
 	}
 
diff --git a/qtfred/src/mission/dialogs/CampaignEditorDialogModel.cpp b/qtfred/src/mission/dialogs/CampaignEditorDialogModel.cpp
index 9663ea83b9e..6455baedc83 100644
--- a/qtfred/src/mission/dialogs/CampaignEditorDialogModel.cpp
+++ b/qtfred/src/mission/dialogs/CampaignEditorDialogModel.cpp
@@ -151,8 +151,8 @@ void CampaignEditorDialogModel::initializeData(const char* filename)
 		}
 
 		// Copy ship and weapon permissions from the global Campaign struct
-		m_ships_allowed.assign(Campaign.ships_allowed.begin(), Campaign.ships_allowed.end());
-		m_weapons_allowed.assign(Campaign.weapons_allowed.begin(), Campaign.weapons_allowed.end());
+		m_ships_allowed = Campaign.ships_allowed;
+		m_weapons_allowed = Campaign.weapons_allowed;
 
 	} else {
 		// CREATING A NEW CAMPAIGN
@@ -164,9 +164,6 @@ void CampaignEditorDialogModel::initializeData(const char* filename)
 		m_campaign_type = CAMPAIGN_TYPE_SINGLE;
 		m_num_players = 0;
 		m_flags = CF_DEFAULT_VALUE;
-
-		m_ships_allowed.assign(ship_info_size(), false);
-		m_weapons_allowed.assign(weapon_info_size(), false);
 	}
 
 	// Load the list of available mission files from the directory.
@@ -319,8 +316,8 @@ void CampaignEditorDialogModel::commitWorkingCopyToGlobal()
 	Campaign.custom_data = m_custom_data;
 
 	// Copy ship and weapon permissions
-	Campaign.ships_allowed.assign(m_ships_allowed.begin(), m_ships_allowed.end());
-	Campaign.weapons_allowed.assign(m_weapons_allowed.begin(), m_weapons_allowed.end());
+	Campaign.ships_allowed = m_ships_allowed;
+	Campaign.weapons_allowed = m_weapons_allowed;
 
 	// Copy mission data
 	for (int i = 0; i < Campaign.num_missions; ++i) {
@@ -1581,7 +1578,7 @@ SCP_vector<std::tuple<SCP_string, int, bool>> CampaignEditorDialogModel::getAllo
 	SCP_vector<std::tuple<SCP_string, int, bool>> ship_list;
 	for (int i = 0; i < static_cast<int>(Ship_info.size()); i++) {
 		if (Ship_info[i].flags[Ship::Info_Flags::Player_ship]) {
-			ship_list.emplace_back(Ship_info[i].name, i, m_ships_allowed[i]);
+			ship_list.emplace_back(Ship_info[i].name, i, m_ships_allowed.contains(i));
 		}
 	}
 	return ship_list;
@@ -1589,9 +1586,13 @@ SCP_vector<std::tuple<SCP_string, int, bool>> CampaignEditorDialogModel::getAllo
 
 void CampaignEditorDialogModel::setAllowedShip(int ship_class_index, bool allowed)
 {
-	if (SCP_vector_inbounds(m_ships_allowed, ship_class_index)) {
-		if (m_ships_allowed[ship_class_index] != allowed) {
-			m_ships_allowed[ship_class_index] = allowed;
+	if (Ship_info.in_bounds(ship_class_index)) {
+		if (m_ships_allowed.contains(ship_class_index) != allowed) {
+			if (allowed) {
+				m_ships_allowed.insert(ship_class_index);
+			} else {
+				m_ships_allowed.erase(ship_class_index);
+			}
 			set_modified();
 		}
 	}
@@ -1602,7 +1603,7 @@ SCP_vector<std::tuple<SCP_string, int, bool>> CampaignEditorDialogModel::getAllo
 	SCP_vector<std::tuple<SCP_string, int, bool>> weapon_list;
 	for (int i = 0; i < static_cast<int>(Weapon_info.size()); i++) {
 		if (Weapon_info[i].wi_flags[Weapon::Info_Flags::Player_allowed]) {
-			weapon_list.emplace_back(Weapon_info[i].name, i, m_weapons_allowed[i]);
+			weapon_list.emplace_back(Weapon_info[i].name, i, m_weapons_allowed.contains(i));
 		}
 	}
 	return weapon_list;
@@ -1610,9 +1611,13 @@ SCP_vector<std::tuple<SCP_string, int, bool>> CampaignEditorDialogModel::getAllo
 
 void CampaignEditorDialogModel::setAllowedWeapon(int weapon_class_index, bool allowed)
 {
-	if (SCP_vector_inbounds(m_weapons_allowed, weapon_class_index)) {
-		if (m_weapons_allowed[weapon_class_index] != allowed) {
-			m_weapons_allowed[weapon_class_index] = allowed;
+	if (Weapon_info.in_bounds(weapon_class_index)) {
+		if (m_weapons_allowed.contains(weapon_class_index) != allowed) {
+			if (allowed) {
+				m_weapons_allowed.insert(weapon_class_index);
+			} else {
+				m_weapons_allowed.erase(weapon_class_index);
+			}
 			set_modified();
 		}
 	}
diff --git a/qtfred/src/mission/dialogs/CampaignEditorDialogModel.h b/qtfred/src/mission/dialogs/CampaignEditorDialogModel.h
index c7616547c8e..ad0eb0b10c2 100644
--- a/qtfred/src/mission/dialogs/CampaignEditorDialogModel.h
+++ b/qtfred/src/mission/dialogs/CampaignEditorDialogModel.h
@@ -187,8 +187,8 @@ class CampaignEditorDialogModel : public AbstractDialogModel {
 	int m_campaign_type = CAMPAIGN_TYPE_SINGLE;
 	int m_num_players = -1;
 	int m_flags = 0;
-	SCP_vector<bool> m_ships_allowed;
-	SCP_vector<bool> m_weapons_allowed;
+	SCP_set<int> m_ships_allowed;
+	SCP_set<int> m_weapons_allowed;
 	SCP_map<SCP_string, SCP_string> m_custom_data;
 	SCP_vector<CampaignMissionData> m_missions;