Re: a 150-mile range
I'm thinking one Marine per "taxi", with mid-size caliber weaponry, flying in support of ground troops with the ability to evac a few injured troops once some of the ammo weight has been removed. Stationing them 10 miles behind the lines would give them quite a bit of time over the lines, and essentially being electric helicopters they'd be hard to locate and hit by enemy ground troops. These guys could likely pop up from behind a tree or any other small obstruction 15 meters from enemy troops, buzz them with automatic fire and drop back down again before anyone knew what happened. Be a lot better at close support than jet aircraft, but I can't imagine being better than a few A10 Warthogs floating around topside.
Future iterations would just do away with the Marine pilot, to be replaced with Tesla's Autopilot system. The enemy war effort would be stopped when ambulances and little kids were shot up. Injured enemy troops could neither be evacuated nor replaced after that deployment.