1) US- Canada military acronym 2) US-Canada defense acronym 3) US-Canada defense letters 4) US-Canada defense system 5) US-Canada military acronym 6) US-Canada security acronym 7) US-Canadian air command 8) US-Canadian defense acronym 9) US-Canadian defense group 10) Aerospace warning org 11) Air Defense group 
North American Air Defense Command (USA).
abbreviation: North American Aerospace Defense Command
a joint U.S.-Canadian air force command responsible for detecting aircraft and space vehicles deemed a threat to the continental airspace.