Air Transport Association 
Advanced Technology Attachment 
Actual Time of Arrival 
Army Technical Architecture 
Advanced Tactical Aircraft 
Agrarische Termijnmarkt Amsterdam 
Allen Telescope Array 
American Trucking Association 
Ammonia Tank Assembly 
Automatic Target Acquisition 
Automatic Trouble Analysis 
AT Attachment 
Auxiliary Ocean Tug 
American Telemedicine Association 
atmospheres absolute 
Aerospace Testing Alliance 
Airport Traffic Area 
American Telemarketing Association 
Analog Terminal Adapter 
ASTRA 
Avionics Test Article 
Abort Timing Assembly 
Acctual Time Of Arrival 
air to air 
Air Transport Association of America 
Air Transport Auxiliary 
Airlift Tanker Association 
alimentary toxic aleukia 
Alliance for Technology Access 
American Tinnitus Association