I was flying a self-made B-26 mission, and the formation was set to "Box". It was an 8-ship formation. Soon after takeoff, I noticed that my fellow AI pilots, especially those in the back row of the box, were constantly swerving all over the place, completely ruining the formation. In fact, there could not form the box formation at all without one plane getting too close to another, which would send if flying to the side, which would start a chain reaction as each plane got too close to the one next to it, until the formation completely dissolved. Before the planes could reform, the process would start again.
The only way to solve it is to warp. However, if you come out of warp and start climbing or turning, the formation will start dissolving again.
This would just be stupid and annoying were it not for the fact that your bombers will frequently collide with you, which is a real bummer when you've taken the time to fly from England to Berlin.
Also, the AI planes occasionally collide with themselves in formation. Now that I mention it, the AI planes frequently crash into each other or plow into the ground on takeoff, too.
This is crap. Doesn't MS play test?