Air brakes are a different set of problems, says the master heavy truck tech. with a class A CDL..... And yes, in many states you would need an endorsement to drive a vehicle with air brakes regardless of GVW. Air brakes do work well in heavy trucks, no question.

Many years ago, I saw an old Dodge 2 ton with the smallest air brake setup I have ever seen. It had 20" 6 stud wheels, the drums were maybe 14". Single cylinder air cooled compressor. I thought at the time you could just about put all that hardware in a dually pickup.