PS: it’s much quicker to walk across the border than to drive. Even with bags, it will take her no longer than 15 mins on foot to walk across and then cross the road for the airport. Airport departures is 50 yards the other side of the border. She will need to carry her own bags though - there are no trolleys (or you could park the car in one of the many car parks close to the border on the Spanish side and cross with her)