Suggestions for conditioning horses to Hot Air Balloons.?

you are right they most horses dont like the roar that comes from the burner,the closest thing i have found is a propane construction heater,they put out a roar that is not as loud as one from a balloon but has the same effect.the only other thing i can suggest is find out when they are doing a flight and trailer your horse close to the take off point so he can get used to the sound.i live near a small airport and several military bases so i have aircraft and big helicopters that fly overhead and my horses dont even look up anymore.heck i even have a stunt pilot that likes to practice over my property (one of these days i will get a clean shot...kidding !) i tracked him down at the airport and told him to make sure he crashes on my neighbors property not mine.lol