Can't figure it out either. I think I knocked one point off the health by using the tow rope on one of my copters, and then doing something after that. I've tried bringing him past the guns when he's on my tow line.
wow! thanks evilmunky! That had to be the easiest, yet most nonintuitive lego chapter every.
If you're in co-op, it's obvious b/c your friend will see the pink targets if you tow the bi-plane; unfortunately, you don't get the target in single player until after you switch to batman. But easy to kill once you see the pink target.