IF you are required to have a CDL, and IF your vehicle has air brakes... then you must have an air brake endorsement. BUT if you are not required to have a CDL to operate the vehicle... then it doesn't matter what kind of brakes you have... air or otherwise.
Beware also that the Federal requirements for CDL is minimum for all states.... BUT.. states CAN require more than the Federal requirements.... ie: The exemption for Apiaries... may not be exempted in certain states. UNLESS it is exempted in your state of registration. In my understanding is... if you are legally registered/ licensed in YOUR state, then you are legal in all states that have reciprocity with your state... and most states have signed this reciprocity. PHYSICAL regulations still apply in each individual state... speed limits/ load limits/ etc etc... but License and registration is only controlled by your home of registration.
I drive a Cabover tractor (registered as motorhome) pulling a 40' RV (42,000# gross) and I do NOT have a CDL... and is not required in any state that has reciprocity with Mississippi... RV's are exempted from all CDL requirements in MS
If you are hauling your OWN bees... have farm plates.... are we SURE we need a CDL, or DOT#? After reading all of this I still don't know. I am going to check what MY state requires... and that should be legal anywhere else. IMHO