[1945] A few years ago, the U.S. Air Force awarded a $6.4 to $7.5 billion dollar contract to seven private companies to provide aggressor air combat training services to the Air Force through 2024. That huge sum is all dedicated to one goal: sharpening the skills of Air Force fighter pilots by putting them in realistic air battles against foreign jet fighters.
The U.S. military introduced aggressor squadrons back in the 1960s after learning in air combat over Vietnam that fighter jocks needed to practice fighting dissimilar aircraft using dissimilar tactics. Just because those aircraft might be deemed technologically inferior didn't mean their pilots couldn't cleverly employ them in ways that exploited weaknesses in American fighters and pilot training.
For example, the supersonic American F-4 Phantom had sophisticated radar and Sparrow missiles that allowed them to engage subsonic, cannon-armed MiG-17 fighters from miles away. But the North Vietnamese naturally didn't go along with the American playbook.