Motorized combat uses streamers that you try to cut, mid-airs are accidental.

Full Contact generally is reserved to Slope combat where the planes are made out of EPP foam and there is no hard metal or wood for the first 1.5 inches. This makes midairs just bumps that you try to knock the other guy outta the air with. After which the pilot usually can just recover and relaunch.

Due to the high number of un-intentional midairs in motorized combat, they tend to build their aircraft as tough as possible. Headon collisions are still usually fatal but side swipes are livable. Some folks do try the full contact combat but you have to worry about having a fuselage taking off with the engine running full power and out of control towards somebody, not a good situation and hard to explain to someone that you actually MEANT to do that.