Make the fly flag an enum flag instead. It now accepts: true, false and default, where default is the default value, and does not change the flight status at all.

Core/src/main/java/com/github/intellectualsites/plotsquared/plot/config/Captions.java

@@ -567,13 +567,15 @@ public enum Captions implements Caption {
     FLAG_CATEGORY_ENUM("Generic Enum Flags", "Flags"),
     FLAG_CATEGORY_DECIMAL("Decimal Flags", "Flags"),
     FLAG_CATEGORY_BOOLEAN("Boolean Flags", "Flags"),
+    FLAG_CATEGORY_FLY("Flight Flags", "Flags"),
     FLAG_CATEGORY_MIXED("Mixed Value Flags", "Flags"),
     //</editor-fold>
     //<editor-fold desc="Flag descriptions">
     FLAG_DESCRIPTION_ENTITY_CAP("Set to an integer value to limit the amount of entities on the plot.", "Flags"),
     FLAG_DESCRIPTION_EXPLOSION("Set to `true` to enable explosions in the plot, and `false` to disable them.", "Flags"),
     FLAG_DESCRIPTION_MUSIC("Set to a music disk ID (item name) to play the music disc inside of the plot.", "Flags"),
-    FLAG_DESCRIPTION_FLIGHT("Set to `true` to enable flight within the plot when in survival or adventure mode.", "Flags"),
+    FLAG_DESCRIPTION_FLIGHT("Set to `true` to enable flight within the plot when in survival or adventure mode,"
+        + " set to `default` to use the gamemode default, and `false` to disable flight entirely.", "Flags"),
     FLAG_DESCRIPTION_UNTRUSTED("Set to `false` to disallow untrusted players from visiting the plot.", "Flags"),
     FLAG_DESCRIPTION_DENY_EXIT("Set to `true` to disallow players from exiting the plot.", "Flags"),
     FLAG_DESCRIPTION_DESCRIPTION("Plot description. Supports '&' color codes.", "Flags"),

Core/src/main/java/com/github/intellectualsites/plotsquared/plot/flags/GlobalFlagContainer.java

@@ -8,6 +8,7 @@ import com.github.intellectualsites.plotsquared.plot.flags.implementations.Block
 import com.github.intellectualsites.plotsquared.plot.flags.implementations.BlockIgnitionFlag;
 import com.github.intellectualsites.plotsquared.plot.flags.implementations.BlockedCmdsFlag;
 import com.github.intellectualsites.plotsquared.plot.flags.implementations.BreakFlag;
+import com.github.intellectualsites.plotsquared.plot.flags.implementations.CoralDryFlag;
 import com.github.intellectualsites.plotsquared.plot.flags.implementations.DenyExitFlag;
 import com.github.intellectualsites.plotsquared.plot.flags.implementations.DenyTeleportFlag;
 import com.github.intellectualsites.plotsquared.plot.flags.implementations.DescriptionFlag;
@@ -19,7 +20,7 @@ import com.github.intellectualsites.plotsquared.plot.flags.implementations.Entit
 import com.github.intellectualsites.plotsquared.plot.flags.implementations.ExplosionFlag;
 import com.github.intellectualsites.plotsquared.plot.flags.implementations.FarewellFlag;
 import com.github.intellectualsites.plotsquared.plot.flags.implementations.FeedFlag;
-import com.github.intellectualsites.plotsquared.plot.flags.implementations.FlightFlag;
+import com.github.intellectualsites.plotsquared.plot.flags.implementations.FlyFlag;
 import com.github.intellectualsites.plotsquared.plot.flags.implementations.ForcefieldFlag;
 import com.github.intellectualsites.plotsquared.plot.flags.implementations.GamemodeFlag;
 import com.github.intellectualsites.plotsquared.plot.flags.implementations.GrassGrowFlag;
@@ -60,7 +61,6 @@ import com.github.intellectualsites.plotsquared.plot.flags.implementations.Serve
 import com.github.intellectualsites.plotsquared.plot.flags.implementations.SnowFormFlag;
 import com.github.intellectualsites.plotsquared.plot.flags.implementations.SnowMeltFlag;
 import com.github.intellectualsites.plotsquared.plot.flags.implementations.SoilDryFlag;
-import com.github.intellectualsites.plotsquared.plot.flags.implementations.CoralDryFlag;
 import com.github.intellectualsites.plotsquared.plot.flags.implementations.TamedAttackFlag;
 import com.github.intellectualsites.plotsquared.plot.flags.implementations.TamedInteractFlag;
 import com.github.intellectualsites.plotsquared.plot.flags.implementations.TimeFlag;
@@ -96,7 +96,6 @@ public final class GlobalFlagContainer extends FlagContainer {
         // Register all default flags here
         // Boolean flags
         this.addFlag(ExplosionFlag.EXPLOSION_FALSE);
-        this.addFlag(FlightFlag.FLIGHT_FLAG_FALSE);
         this.addFlag(UntrustedVisitFlag.UNTRUSTED_VISIT_FLAG_TRUE);
         this.addFlag(DenyExitFlag.DENY_EXIT_FLAG_FALSE);
         this.addFlag(DescriptionFlag.DESCRIPTION_FLAG_EMPTY);
@@ -150,6 +149,7 @@ public final class GlobalFlagContainer extends FlagContainer {
         this.addFlag(WeatherFlag.PLOT_WEATHER_FLAG_OFF);
         this.addFlag(DenyTeleportFlag.DENY_TELEPORT_FLAG_NONE);
         this.addFlag(TitlesFlag.TITLES_NONE);
+        this.addFlag(FlyFlag.FLIGHT_FLAG_DEFAULT);
 
         // Integer flags
         this.addFlag(AnimalCapFlag.ANIMAL_CAP_UNLIMITED);

Core/src/main/java/com/github/intellectualsites/plotsquared/plot/flags/implementations/FlightFlag.java

@@ -1,19 +0,0 @@
-package com.github.intellectualsites.plotsquared.plot.flags.implementations;
-
-import com.github.intellectualsites.plotsquared.plot.config.Captions;
-import com.github.intellectualsites.plotsquared.plot.flags.types.BooleanFlag;
-import org.jetbrains.annotations.NotNull;
-
-public class FlightFlag extends BooleanFlag<FlightFlag> {
-
-    public static final FlightFlag FLIGHT_FLAG_FALSE = new FlightFlag(false);
-
-    protected FlightFlag(final boolean value) {
-        super(value, Captions.FLAG_DESCRIPTION_FLIGHT);
-    }
-
-    @Override protected FlightFlag flagOf(@NotNull Boolean value) {
-        return new FlightFlag(value);
-    }
-
-}

Core/src/main/java/com/github/intellectualsites/plotsquared/plot/flags/implementations/FlyFlag.java

@@ -0,0 +1,64 @@
+package com.github.intellectualsites.plotsquared.plot.flags.implementations;
+
+import com.github.intellectualsites.plotsquared.plot.config.Captions;
+import com.github.intellectualsites.plotsquared.plot.flags.PlotFlag;
+import org.jetbrains.annotations.NotNull;
+
+public class FlyFlag extends PlotFlag<FlyFlag.FlyStatus, FlyFlag> {
+
+    public static final FlyFlag FLIGHT_FLAG_DISABLED = new FlyFlag(FlyStatus.DISABLED);
+    public static final FlyFlag FLIGHT_FLAG_ENABLED = new FlyFlag(FlyStatus.ENABLED);
+    public static final FlyFlag FLIGHT_FLAG_DEFAULT = new FlyFlag(FlyStatus.DEFAULT);
+
+    protected FlyFlag(final FlyStatus value) {
+        super(value, Captions.FLAG_CATEGORY_BOOLEAN, Captions.FLAG_DESCRIPTION_FLIGHT);
+    }
+
+    @Override public FlyFlag parse(@NotNull final String input) {
+        switch (input.toLowerCase()) {
+            case "true":
+            case "enabled":
+            case "allow":
+                return FLIGHT_FLAG_ENABLED;
+            case "false":
+            case "disabled":
+            case "disallow":
+                return FLIGHT_FLAG_DISABLED;
+            default:
+                return FLIGHT_FLAG_DEFAULT;
+        }
+    }
+
+    @Override public FlyFlag merge(@NotNull final FlyStatus newValue) {
+        if (newValue == FlyStatus.ENABLED || this.getValue() == FlyStatus.ENABLED) {
+            return FLIGHT_FLAG_ENABLED;
+        }
+        return flagOf(newValue);
+    }
+
+    @Override public String toString() {
+        return this.getValue().name().toLowerCase();
+    }
+
+    @Override public String getExample() {
+        return "true";
+    }
+
+    @Override protected FlyFlag flagOf(@NotNull final FlyStatus value) {
+        switch (value) {
+            case ENABLED:
+                return FLIGHT_FLAG_ENABLED;
+            case DISABLED:
+                return FLIGHT_FLAG_DISABLED;
+            default:
+                return FLIGHT_FLAG_DEFAULT;
+        }
+    }
+
+    public enum FlyStatus {
+        ENABLED,
+        DISABLED,
+        DEFAULT
+    }
+
+}

Core/src/main/java/com/github/intellectualsites/plotsquared/plot/listener/PlotListener.java

@@ -124,7 +124,8 @@ public class PlotListener {
                 }
             }
 
-            if (plot.getFlag(FlightFlag.class)) {
+            final FlyFlag.FlyStatus flyStatus = plot.getFlag(FlyFlag.class);
+            if (flyStatus != FlyFlag.FlyStatus.DEFAULT) {
                 boolean flight = player.getFlight();
                 GameMode gamemode = player.getGameMode();
                 if (flight != (gamemode == GameModes.CREATIVE
@@ -132,7 +133,7 @@ public class PlotListener {
                     player.setPersistentMeta("flight",
                         ByteArrayUtilities.booleanToBytes(player.getFlight()));
                 }
-                player.setFlight(true);
+                player.setFlight(flyStatus == FlyFlag.FlyStatus.ENABLED);
             }
 
             final GameMode gameMode = plot.getFlag(GamemodeFlag.class);
@@ -299,7 +300,8 @@ public class PlotListener {
                 }
             }
 
-            if (plot.getFlag(FlightFlag.class)) {
+            final FlyFlag.FlyStatus flyStatus = plot.getFlag(FlyFlag.class);
+            if (flyStatus != FlyFlag.FlyStatus.DEFAULT) {
                 if (player.hasPersistentMeta("flight")) {
                     player.setFlight(
                         ByteArrayUtilities.bytesToBoolean(player.getPersistentMeta("flight")));