Yes, indeed. . . Anti-Aircraft guns are for shooting at aircraft. Although I do find that their function in this role is sketchy at best. Rarely will you shoot down an enemy plane. Instead, as I understand it, the presence of AA can distract enemy's aircraft and keep it from doing its job effectively. I do find, however, that smaller caliber AA works VERY well against targets on teh ground. Just the other day, I played a game iin which my soviet 37mm shot up a number of Pz IIIs, a couple ACs and tagged a few inf. as well. The key to this, as with all artillery pieces, is PLACEMENT. Find your weapon a nice, cozy spot to camp in.
Ah. . . I was a newbie once. . .
Anyway. . . I guarantee that you will enjoy this game.