You know, I don't even think Alto is in the cockpit at the point he is shot. He flies behind the wrecked ship, Klan takes on Harmonica, and then we see Alto's 117 fly back into the picture with no shot of Alto in the cockpit (come on, we ALWAYS get a shot of the pilots in the cockpit, yelling and being all gar and stuff), it gets shot (still no shot of Alto reacting), and it flies up and away and blows up.
Forget him bailing after he's shot, dude wasn't even in the 117 when it get nailed.