diff --git a/game/operation/operation.py b/game/operation/operation.py
index 1e586be0..4d690a8d 100644
--- a/game/operation/operation.py
+++ b/game/operation/operation.py
@@ -347,6 +347,7 @@ class Operation:
         cls.airgen = AircraftConflictGenerator(
             cls.current_mission, cls.game.settings, cls.game,
             cls.radio_registry, cls.unit_map)
+        cls.airgen.clear_parking_slots()
 
         cls.airgen.generate_flights(
             cls.current_mission.country(cls.game.player_country),
diff --git a/gen/aircraft.py b/gen/aircraft.py
index 05c33f69..f16ede99 100644
--- a/gen/aircraft.py
+++ b/gen/aircraft.py
@@ -911,7 +911,6 @@ class AircraftConflictGenerator:
 
     def generate_flights(self, country, ato: AirTaskingOrder,
                          dynamic_runways: Dict[str, RunwayData]) -> None:
-        self.clear_parking_slots()
 
         for package in ato.packages:
             if not package.flights: