I can't fly 2 ships at once, so how to I move a ship to a new hanger location?
You cannot....Unfortunately .....
You could sell ( ie eagle ) and buy another at a location you prefer but that's about it at the moment..
Suggestion I saw elsewhere, weeks ago: Fly ship A to new location. Garage it there and buy a Sidewinder. Strip Sidewinder to get maximum jump range (for convenience), then fly it back to where ship B is garaged. Sell off Sidewinder and take ship B to new location.
Not the most convenient, but the process gives you a temporary goal, and the hazard involved in flying a stripped-down Sidey may amount to a bit of an adventure as well.