A1 was airborne, so a shooting foul committed against A1 can be called for contact resulting before A1 has their first foot back on the ground.
This play exhibits the necessity to continue to watch the players, and nothing else. It's similar to a field judge in football watching only the players' actions as the ball comes down, because he knows it will come down! (The apple discovery proves it!
)
After a player has released the ball, I allow more contact (not
a lot more though) on the arm, because the arm usually isn't used to land. If I'm certain that A1 would have had to use his arm to land safely, and his arm is whacked out of position and A1 now lands awkwardly, I've got a foul.