Question bout Aircraft

[CSA FD]

ok, ive completed brit supplies/costal waters and the total Germany campain, my question is: AIRCRAFT, i see them constanly on the map, and alot of the times they fly directly over head, and i target them with my AA and they fire way below the targets, i got one where i was the one aiming (swordfish, which doesnt have much speed) how do i get them to aim @ the aircraft and do aircraft even attack subs? (not that i want them too, just wondering)