AC electrical buses are common in airplanes from light piston twins all the way up to the largest airliners. I usually see both a 115v and 36v AC bus with a 400 Hz output frequency. How do most airplanes regulate the output frequency coming from the AC generator?
It's done using mechanical device called constant speed drive. Works almost the same as CVT transmission in a cars. The more complex thing is phase adjustment as airplane usually has multiple engines and generators. But that is not done as different generators always power different buses!