I firmly believed the opposite for a while, and settled for him having a really average air game.
Strong disjointed attacks are good on paper, but in practice, they're nothing great, thanks to his horrendous air mobility. Luckily we have fast fall, which makes using aerials when only slightly above the ground decent.
Our aerials are good, but our air game isn't, if that makes sense.
FF Bair is amazing for edgeguarding; there's generally very little room for people to respect it off-stage.
However on stage, it becomes extremely telegraphed and pretty unreliable. Unreliable basically define most of TripleD's on stage game anyway.
To answer the OP, you'll need to know the timing on your aerials, as Jax stated so you can land fast-falled aerials effectively. If you're airborne and your opponent is on the ground commititng to any kind of move, you can sometimes surprise them with a FF Fair.
SH FF Nair is a great punish to rolls on reaction, which combos into UpTilt(s) at lower %.
I believe approaching with aerials isn't really that good. Bair can safely poke shields, but doesn't really accomplish anything. If you need to approach, you're probably better off SHFF over whatever blocks your path and space with FTilt.
Our ground/low air game is really where it's at; use your air game for edgeguarding, not much else.