But bang has all sorts of really good options in air - he can also j.a, j.b and J.c - he has normals for each air direction, double airdash, can cancel air movement with a kunai...he can 623b if he really wanted to...
Meeting bang in air just sounds like a bad idea, especially when j.a, while fast, is not as range-friendly as J.b[m] or J.c[m]
Bang doesn't have good AA, but neither does litchi. timing the 2A AA is hard because he'll just J.c, you really have to make him think he's going to hit or crossup, which requires you to know if you have to backdash, cross under, or what.
5A AA doesn't work well for me against bang.
2C is too slow.
I have never managed to 2A AA anything.