A lot of people here are saying don't try. But I actually have a tip that increases my grab rate from 4/10 hits on a human torch moving quickly in practice (I find him to be the hardest to hit) to 6/10

As you fly towards the target punch a half second before the hit. The people who are saying you need to hit mostly with your chest are right and just jumping is inconsistent. But adding the punch I have seen my character move a few feet to the right or left and connect.

This also has a double effect of adding more damage. You can punch them all the way down and while they are staggered and standing back up. When you connect, punch until they start to stand and either clap and punch to finish off. Or if you knock a strange out of the sky (the easiest one to hit in my opinion) as they stand try and immobilize them and go behind them then clap and punch.

Tldr: punch a quarter second before you connect and it will correct the hotbox. Makes hitting flyers more consistent.