def METHOD_NAME(self) -> None:
    """Create iterable to display allied flights grouped by departure airfield."""
    for flight in self.flights:
        if not flight.client_units and flight.friendly:
            name = flight.departure.airfield_name
            if (
                name in self.allied_flights_by_departure
            ):  # where else can we get this?
                self.allied_flights_by_departure[name].append(flight)
            else:
                self.allied_flights_by_departure[name] = [flight]