Once your flight is booked, one of the best ways to save time at the airport is to check-in in advance. Almost all airlines will send you an email reminder 24 hours before your flight. Take five minutes to check-in to your flight, and save yourself from the long check-in lines full of people not as smart as you. More and more airlines are also now accepting e-tickets that you can save and display on your smartphone, making it that much easier.