[Maverick]

Well I think the main reason is because the fighters arn't just space fighters, they were designed to be mainly used in an atmosphere originally. If they were designed to be space fighters why did they include Wings and a Rudder hun? No use what so ever... in a space enviroment

that's why I didn't say anything about wings, my point is that if the engines can generate thrust in space, then just like a rocket, they can work in the atmosphere too. Anyway you can think in any obscure reason for the air intakes, a nuclear powered jet is already a fishy concept, you can't generate thrust with a nuclear reaction alone, you need a reaction mass, and blah blah blah ... see the Orion Project.

They might be Nuclear powered, but think for a minute... How do Nuke subs move?

The energy produced goes to a heat exchanger that boils water, the steam moves a turbine and then the turbine moves the propeller or an electricity generator. It's a steam engine, it all comes down to boil some water.