How far does a gravity generator's field extend? I assume that ships and stations have internal gravity, so it could kick in long before you get to the hangar. It could be a field that drops off by the square of the distance, meaning that as you approach a station, you have to acknowledge it as a kind of building in space, with 1g acceleration all around it, fading to 0g acceleration at some distance. So if you fly up under the station, you're actually having to fly under a building, pushing up with your thrusters instead of just floating there underneath it. If you fly over it and turn off your engines, you'll drop and crash into it.
As applied to a hangar approach, you would land as if the station was a building on a planet. You could also land on any 'top' surface of the station.
A hollow cylindrical station could be designed such that gravity is forcing objects out away from the center axis of the station. If you fly right down the center, you're in zero gravity, but as you move off that line, you'd start to get pulled onto the inner surface. Or do it the other way and have a solid cylindrical station and have all the gravity pulling towards the center axis of the station. Land on the outer surface of the cylinder.