Airman has a stupid-easy pattern. Dodge 3 waves of Air Shooters (they don't deal much damage IMO compared to later bosses), have him jump to you after the third wave, put some lead in, keep going until he's dead.
I only took about one or two hits, no E Tanks, no save-stating.
Yea, most, though not all of MM2's Masters aren't really a challenge. Probably Quick, Crash, and to a lesser extent Bubble Man are the more troublesome of the masters since Bubble Man doesn't really run on a pattern, Crash fires his Crash Bombs at fast speeds, and Quick Man does what earned him his name and has projectiles that are hard to dodge.
If you want a hard Air Man, the rom hack "ROCK'n MAXX" would be your thing; Speedy Air Shooters with only so much room to avoid each, and your Buster only does 1 unit of damage per shot to him. There's also Rockman Cross X (a MM5 hack), which employs Air Man with an entirely new strategy.