Why did backseater (two-man) fighter planes fall out of favor?

Errr… yeah. Yes, it is. hangs head

It’s Okay. It’s been a long year, all around. Have some bubbly, and sleep in tomorrow.

There was a time, though - way back pre-WW2 when the Army wanted to keep the Air Corps small and unimportant - when the main role of airpower was ground support. The planes that did this were O- (observation) and A- (attack) series planes, and they were all two-seaters - single-engine ships with a light bomb load and a gunner’s position, a lot like dive bombers except not designed to dive. These were no longer part of the battle plan by the time of Pearl Harbor, although a couple of twin-engine attack planes (A-20 and A-26) served admirably as fast, light bombers in WW2.

There was even a fighter gunship, the Bell Airacuda, around 1938. It carried aerial cannon and a crew of 5, and was meant to intercept bombers, but (like many US warplanes of the day) was simply too slow.