The Institute of Medicine released two seminal reports in 1999 and 2001.The first report, To Err is Human: Building a Safer Health System released in 1999 received enormous publicity and focused attention on the issues of medical error and patient safety.
The general rule of thumb is that one is supposed to arrive. 1  2 hours early for a domestic flight and. 2  3 for an international flight.
The Transportation Security Administration agrees with it, but airlines don't. For instance, American Airlines advises passengers to be at the airport two hours before flight time for international departures and 90 minutes for domestic flights. Also, there's an exception for flights to certain overseas destinations, which require that you check in earlier.