Yeah, Bison is the keyword. Bison upgrades keep the MiG-21s
viable in the air to air arena, taking out it away from the ground
support role. Basically, the further it is from the ground, the
safer it is to fly, in a way. =D
So if u ever have a MiG-21 on ur tail, at dogfight range. Take your
fight low, and keep making him rack up his AOA. He might just
crash. =D