Hey I really liked this. Reminded me a tiny bit of Lander on the Archimedes, Hardwar (underrated!), Wing Commander-y visuals.

The extensions suggest themselves - some progression (financial) beyond merely guild hierarchy; some adversarial element (could be economical like bidding for routes.)

Only bit I struggled with was the car-like handling when you turn left and right; I would expect you to orient using yaw axis and then have to use thrust to change your velocity vector. But it certainly is simpler the way you have it.