Several airlines this month tightened rules on check-in times, luggage and connecting flights to cope with new baggage-screening procedures that went into effect Jan. 18.
Delta Air Lines will no longer accept checked baggage at ticket counters or curbside less than 30 minutes before flight time. Passengers with checked baggage who plan to fly standby must announce their intention at check-in, Delta said.
Continental Airlines requires fliers to check in at the gate at least 15 minutes before their flight, even if they checked in previously, or possibly lose their seat.
United Airlines advises customers to arrive at the airport at least 90 minutes before domestic flights and two hours before international flights. If they decide at the last minute not to take a flight, the airline said, "it's imperative to notify a customer service representative immediately."