The US Airways online check-in process opens 24 hours before the scheduled departure time for a specific flight. Passengers have access to online check-in until 45 minutes before the scheduled departure time on domestic flights and 90 minutes before the scheduled departure time for international flights.
If a passenger has less than 45 minutes before a domestic flight or 90 minutes before an international flight, check-in at the airport is required. US Airways requires all passengers to check in at least 30 minutes before domestic flights and 60 minutes before international flights even at the airport. Passengers assigned to an exit row must check in at the airport with an agent.