Realistic?
The source of your expertise, please?
Obviously, the plot was more than a little unrealistic - but the air-to-air stuff was very impressive. Contrast that with the aviation movies filmed with actors in dummy cockpits, grimacing at the enemy. Scenes in which they changed aircraft in scenes from one kind to another - or in some lame Korean War movies, swapped jets for prop planes and then back again! These actors were really flying and sustaining some serious Gs!