Minimum Requirement for Ships in TW

Each unit must be 6kgp. The units in fleet are the ships, not the pilots. Ignore the pilot GP.

The ship GP on its own must be 6kgp. 

Of course you raise ship GP in part by raising pilot GP, but you don't get to add pilot and ship together. Just look at the ship's GP. That's all that matters. It it's below 6k, do anything you can to boost in, whether that's adding levels & ability increases to the ship or whether that's improving the pilot doesn't matter. Just look for that ship to cross the 6k gp line by itself.