If you prefer to check in at the airport, you can do so at the check-in counters.
All US & Canadian airports, except Orlando (MCO)
Check-in opens 2 hours before the scheduled departure time and closes 40 mins before scheduled departure time.
Orlando
Check-in opens 3 hours before the scheduled departure time and closes 60 mins before scheduled departure time.
Bermuda
In Bermuda, check-in counters open 2 hours before scheduled departure and close 60 minutes prior to the scheduled departure.