Some nice fixes for ZAS.

code/game/supplyshuttle.dm

@@ -69,18 +69,10 @@ var/list/supply_groups = new()
 	name = "\improper Airtight plastic flaps"
 	desc = "Heavy duty, airtight, plastic flaps."
 
-	New() //set the turf below the flaps to block air
-		var/turf/T = get_turf(src.loc)
-		if(T)
-			T.blocks_air = 1
-		..()
-
-	Del() //lazy hack to set the turf to allow air to pass if it's a simulated floor
-		var/turf/T = get_turf(src.loc)
-		if(T)
-			if(istype(T, /turf/simulated/floor))
-				T.blocks_air = 0
-		..()
+	CanPass(atom/A, turf/T, height = 0, air_group = 0)
+		if(!istype(A))
+			return 0
+		return ..()
 
 /area/supplyshuttle
 	name = "Supply Shuttle"