ULTIMATE MARVEL VS CAPCOM 3

To perform a Team Aerial Combo, you must hit the A button (special attack) and it will knock the opponent into the air. Follow them into the air (Up direction) and do a combo, ending with pressing A again +any direction (A simple combo would be, to knock them in the air, then hit them with any normal attack then A+any direction) It will then bring in your next character and you can continue the combo in that fashion. Do this 50 times (Note, it's every Execution of the combo, bringing in 2 characters throughout the combo still only counts as 1) and you're done.

Easily boosted with a friend on Player Matches if you're having troubles.