Although the process varies state to state, these general steps can help you get started. 1  Replace your birth certificate. Find the vital records office in the state where you were born. 2  Replace your driverâs license. Get this first if you cannot get your birth certificate. 3  Replace your marriage certificate.
The American Airlines website recommends arriving at least 60 minutes early for domestic flights and two hours early for international flights. You must check in at least 30 minutes before a domestic flight and 60 minutes for international flights; otherwise, American Airlines has the right to cancel your ticket.
For bookings made elsewhere, such as with online booking engines or travel agents, you can usually do the same, although some airlines, including Delta, require that you are a frequent flier member in order to log in to use the service. Rules on how long in advance of your flight you can check in varies considerably. Some airlines allow passengers to check-in online within 12-24 hours of departure time to as late as 30 minutes prior to scheduled departure time.