Ok so i know how to grab after the Big ninja cannon

and the normal ninja cannon, also i know the GB kick after "windroll" move.
So are there any other ways to get them high enough to grab or is that pretty much it
Besides, why would you want to do an air grab? You've got a more awesome follow up that looks cooler, is harder to execute, and...DOES 4 EXTRA DAMAGE!
Basically, instead of say...
2A+B 236236A+B+K4 66 8B+G
Why not follow up with a cooler version:
2A+B, 236236A+B+K4 66 4 A+B, FC A+B, 44KK
But yeah, the main problem with air grabs is that if bombs are, in fact, the only way to get them, then they can pretty much always be avoided with jumps, left/right/back ukemi's (to avoid tech traps), or just eating them while grounded.
Though, if you want another way to grab that, you could do the BE PO Weasel Run (PO A+B+K) past your opponent and then use K to grab them. I believe that's the one that grabs.