First of all, if an airline delays or cancels a flight and you miss an important meeting, you cannot successfully sue the airline. The "conditions of contract" that appears on the back of every ticket for a domestic flight are legally binding. They state that schedules are not binding on the airline. Once you hold the ticket, you must live with the rules written on the back regardless of whether you have read them or not.

1. Mechanical problems or delays due to weather may:
2. Force a cancellation.
3. Require an airline to substitute a smaller plane for the originally scheduled one.
4. Cause you to miss a connection.
5. Divert your flight to another airport.

If these occur the airline is legally bound to use its best efforts to get you to your destination either by resuming the original flight as soon as possible, putting you on its next flight with available seats (even if it means putting you in a higher class if your class is filled), or chartering a bus to your final destination.

In the case of a schedule irregularity, i.e., you're delayed at a connecting airport, diverted to an unscheduled airport for more than a few hours, or there was a change in the published schedule that you were not aware of, you may be entitled to some special compensation. This might include a meal or two, long distance phone calls to alert others at your destination, or a hotel room for an overnight delay.

Under most conditions of contract, if the airline cannot put you on an alternative flight, or puts you on a flight that is unacceptable to you, you can request a refund under the involuntary refund rules. But remember, under most of the conditions of contract, the alternative transportation offered has to be acceptable to you. In other words, the alternative has to be so unacceptable as to have caused a provable hardship or loss, in which case, even if your ticket is marked nonrefundable, you are entitled to a refund.

There is also the question of whether the alternative flight or transportation leaves or arrives so much later than your original flight that it is unacceptable, and you decide not to go ahead with any transportation arranged by the delaying/canceling airline. Again, you'd better have a very good reason for refusing the airline's offer and subsequently trying to obtain a refund.

A final word on delays. Before the introduction of Apex and MaxSaver fares, if a flight was canceled or delayed and the airline had no available alternative flights, you could use your regular ticket on another airline, without question. However, with today's restricted tickets, competing fares and short term cut-rate promotions, an airline does not have to "sign over" your original ticket to another airline. And even if it does, the other airline doesn't have to accept it if the value is below the fare charged for a ticket without advance purchase. Welcome to the world of airfare wars!