Callsign ACA is Air Canada
WHAT AIRLINE IS ACA?
ACA is the ICAO three-letter callsign prefix for Air Canada. When a radio scanner, flight tracker or radar scope shows a flight like ACA123 or ACA45XY overhead, that's a Air Canada aircraft talking to air traffic control.
Spot one yourself: open the live scope, enter your postcode, and tap any blip whose callsign starts with ACA for its type, registration, route and photo.