You want to fit 38's or 39's on an air ride? If so, then I think you are out of luck. I believe there are a couple 6 inch lifts which maintain the factory air ride, but not sure you're getting that big a tire under them.
For a simple level you need leveling links and a Day Star spacer kit and from what I can tell you would then be able to fit 35's under her.
Good luck in your search. Also, there are several full threads on lifting with air suspension. None of these threads are very easy to follow, but they are there if you have the time.