[tebbetts]

My guess is that most of the camouflage is to hide the airplane from humans on the ground. I would also guess an airplane providing support for ground troops would likely get shot at.

They would paint a fake canopy on the underside of the Warthog: http://www.flickr.com/photos/arnielee/4105880397/. This was to make it hard to tell which way the airplane was turning.

[electromagnetic]

It might be for take-off and landing too when the planes without typical near-ground combat are now extremely vulnerable. The Warthogs are unbelievably built to go through hell and back, an F-15 not so much.

> They would paint a fake canopy on the underside of the Warthog

I'd just hate that someone painted my exact location on the bottom of my plane so the enemy knows exactly where I'm sitting so they know exactly where to shoot at. I mean I'm sure everyone would know where the pilot is, but this would be like the Imperials painting a massive bullseye target around the ventilation tube on the Death Star.

[hedgehog]

Premature optimization. Shooting an aircraft is kind of like shooting a duck, it's moving fast and hard to hit at all. If you can make it hard to estimate your direction and speed it helps you out a lot.

[ceejayoz]

Anti-aircraft fire isn't like a sniper rifle, it's more like a grenade launcher. You're certainly not going to be aiming for a specific location on a plane - you're going to be aiming in its general direction and throwing as much ordinance at it as possible, in the hopes that shrapnel from one of your shells pegs it.

[mikeash]

The underside of the cockpit is probably the best area to get shot at in an A-10. It's heavily armored, so the pilot is safe, and there are fewer important parts to break there as compared to being shot farther back.

[paxswill]

As support, here's some specific pictures of just the "bathtub": http://www.flickr.com/photos/25695066@N00/sets/7215762746187...