| Cheap Flights: Austin or San Antonio to/from Cancun $222-$256 r/t [September-November] â Aeromexico / Delta Aeromexico, Delta, and American Airlines have round-trip flights from Austin or San Antonio (AUS, SAT) to Cancun (CUN) for $222-$231 with connections. Flights September to November. Extended weekends available. Origin/Destination reversible. Click for more details and booking links Cheap Flights: Austin or San Antonio to/from Cancun $222-$256 r/t [September-November] â Aeromexico / Delta . | 