Well, the ships are very fantasy and I find myself running this game about 1/3 by the seat of my pants.
One, I increased the top speed of an air-ship over its waterborne sister by 20%. While there's no logic behind that, it seems to be cool.
Two, I instituted some light Yaw and Pitch rules. My ships are SEA ships that fly. The culture maintains seaworthiness in airships because the nations they do trade with don't have airships but do have infrastructure in place for waterships. This means you can't just decide to run into a 70 degree climb or you'll lose the wind and half a dozen sailors. This maxes out around 30 degrees or so, with some pilot checks. It could get into alot of math and trig pretty quick but we just eyeball it. "They're too high for you to climb to incercept!" or "The pilot screams that the ridge is too high and you're coming in too fast!" Likewise you can't just open up a broadside on somebody if it involves flipping the ship nearly on her side. I give them some play on the angles, but again, fast and loose. In that first battle, for instance, the pirates came in not just out of the sun, but ABOVE and out of the sun, dropping altitude and coming in at a vector that they'd have several minutes of fire before the PCs could wheel to face. Even then, they had to pull a dangerous larboard list to bring the guns to bear early.
((And, unfortunately, I underestimated the effects of PCs on the fight. It takes so long to fire guns that the Charismatic PC (2nd mate) gave a good argument that he could definately run back and forth on the gun-deck shouting orders (and making Cha checks) to make sure almost every cannon shot had his Coordination bonuses in place) They managed to start soundly trouncing my "insurmountable" pirate attack. I gave everybody 2 APs and fast-forwarded to their ... "defeat" ... since this was the SINGLE pivotal plot point. D'oh! I love GT because they were too busy petting their brand new APs to grumble too much ... and it was a mark of honor for them that they'd managed to beat the tar out of my pirates, even IF they had to "lose" to keep the story moving.))
Beyond that the rules work quite well. I might implement some more "blown off course" rules into storms, but so much air combat runs like sea combat anyway (how often do people just hand-wave altitude) that I haven't had to do too much. It's an RP heavy game anyway, so beyond having fun and being flavorful we're good to go.
((Oh, and I've found that the Pirates of the Spanish Main CCG makes for nifty little ship models. Reasonably affordable too. They loved it when I brought out the little plastic ships ... WITH Jolly Rogers!))
--fje
