There is a way to check a complete flight itinerary online without dealing with airlines or booking agencies. You can find out if your flight is confirmed or not, and get the e-ticket number if e-tickets were issued. Sabre and Amadeus are the two main systems used to book flights regardless of the airline. Each company has its own website with all or most of the information a domestic traveler will need.
When you book your flight, get your GDS reservation code. This is usually different from the airline confirmation number, but a booking agency is likely to give it to you. It is made up of six letters and/or numbers.
Check the code to determine the system it belongs to. Reservation codes starting with 1, 2, 3, 4, 5, X, Y, or Z are from the Amadeus system. Codes starting with anything else are from the Sabre system.
Call up checkmytrip.com if you have an Amadeus code. Enter the GDS reservation code and the passenger's last name.
Go to virtuallythere.com if you have a Sabre code. Enter the GDS reservation code and the passenger's last name.