Question If an applicant does not receive an air brakes endorsement: Answers They cannot operate a vehicle with air brakes. They can only operate a vehicle with air brakes in intrastate commerce. They can only operate a vehicle with air brakes in interstate commerce. Explanation If you wish to be licensed to drive a CMV with air brakes, you must pass the air brakes knowledge test and use a vehicle with air brakes for your skills test. Take a FREE Practice Test Now This questions appears in the following tests: Idaho Knowledge Test Class B , Vermont Knowledge Test Class B ,