Still increases air resistance. It gets hit by air, and that pushes it back into the fuselage.

Larger aircraft commonly have a ram air turbine (RAT) or Air Driven Generator (ADG) to provide some electrical power and hydraulics in certain emergency situations.

On CRJs, it's right up the front: https://www.youtube.com/watch?v=MxgPrpjByTE

Still delivers a percent or two penalty to fuel burn, and the tiny little generator doesn't even come remotely close to making up for that.