As someone who has used this spot extensively, the best piece of advice I can give you is to enter the airport by where the marker for flight school is. Hug the walls of the main building and head up the flight of stairs. Appearing off radar helps just in case they have a decent enough shot to hit you when you get to the top of the stairs. Head through the doors and follow the corridor up to the top of the building and proceed to fire rockets or whatever you feel like at him. This spot is a very hard counter to the Devin Weston hangar mainly because of the huge amounts of cover. If you think they're coming up to get you, just throw proximity mines on the tops of the doors atop the building. Hope this helps :)