Hehe. This is what happens when you are thinking entirely "Inside the Box." Hehe. Another way of putting it is they have blinders on or in their case, Baseball Caps. Same effect. It shields their eyes and prevents them from seeing the threat from above. I'd expect more 3 dimensional thinking from an aviator...
I can't wait to see what happens to Chuck and Julio when they get dumped on in the next strip!
RC