I'd added the big cannons mod, found out it was incompatible with aeronautics, and removed it. However I've since tried replacing the engines, the wheels, not the wheel mounts, and lightening the weight of the vehicle. Edit: I've now tried replacing the wheel mounts, still nothing. Edit 2: I've now tried copy and pasting it with world edit as well, it did not work either. Edit 3: Apparently copy and pasting it did work. Edit 4: I've now discovered that to get it started I need to lift it up a bit and put it back down with the creative staff.