Last name: Kiefer. This interesting and unusual surname is of Germanic origin, and is a metonymic occupational name for a maker or repairer of wooden vessels such as barrels, tubs, casks and vats. The derivation is from the German kief(e), kufe, itself coming from the Old High German kuofa, barrel.
Commercial Driver's License (CDL) A CDL is required to drive any of the following vehicles: Any combination of vehicles with a gross combined weight rating (GCWR) of 26,001 or more pounds, providing the gross vehicle weight rating (GVWR) of the vehicle being towed is in excess of 10,000 pounds.
The short simple answer is you do not need a cdl for a vehicle under 26001 lbs, air brakes or not. If you haul Hazardous material, you need a class c with a hazmat endorsement and you must take your road test in a truck with air brakes and pass the general knowledge test for cdl.