Donnell Rawlings isn't surprised the Delta fight went down in the ATL ... but he says it was totally avoidable if people would just do a few simple things onboard the aircraft.

We got the comedian Sunday at LAX and asked about the Delta brawl where a pilot punched a woman in who was in an all-out brawl with another passenger. He had A LOT to say.

Donnell's not surprised it went down in Atlanta, and his reasoning is pretty hilarious.

As for the pilot ... Donnell says he must've gotten some combat training somewhere ... like a Trump rally or something.