That’s me with the cheesy grin. As I write this, I am sitting in the Indianapolis airport with a fresh and FREE $300 travel voucher in hand. My day just got better. If your travel plans are even a little flexible, you may be able to score some vouchers as well. This system has worked for us in the past. Today is further proof of the method. Here is how it works:

Book your tickets. If you have a layover (or two) even better.
Check in at the airport, and proceed to your gate as soon as you can.
Once at your gate, speak with the gate agent behind the desk. You may be at the gate before the agent. That’s OK. Just wait for them to show. Once they do, let them get settled, then move in for the strike. Ask them “Do you need any volunteers off the flight to [the city you are flying into – not your final destination]?
Most times they will say “No, but thanks for asking.”
Sometimes, like today, they say “Yes, we are. Would you like to volunteer?”
It is at this stage that it gets fun. Here is what happened with me today (and how it can work for you).

Here are some additional considerations:

If they can’t get you out until the next day, they will offer vouchers and will pay for a local hotel room and transportation. They want you off the plane. They have sold extra tickets and the guy taking your seat just paid a ton because he booked it late.
Sometimes they will negotiate the price. When you ask what they are offering, pause and say “Well, what is the most you can offer for compensation?” I forgot to do this today!
Be nice to them and they will be nice to you. They have some negotiating power. Make sure the vouchers will spend like cash. On a past trip, I scored 2 round-trip tickets on US Air. Because they had so many blackout dates, I could not use them. Ridiculous.
The offer from them may go up. The best I ever did was on a flight from Guatemala City to Miami. I volunteered for a $400 voucher. They needed more volunteers and (over the speakers) offered $400 to anyone else who would take the deal. No takers. They upped the offer to $600 and someone volunteered. An agent came to me and said “You will be getting a $600 voucher as well.” That day, I spent 6 hours in the Guatemala airport waiting for a later flight. I’ll take $100 an hour any day.
Your chances are higher if you are flying over peak times. In this economy, as the airlines cut flights and try to pack each plane, I think we will see more flights oversold. Good news for you and me.
Realize that you will get told “no” more than “yes.” In 2007 my family and I flew several flights in the Continental US, Hawaii, and Australia. None of those flights were oversold. Go figure.
More layovers mean more chances of getting on a full flight. Go to the desk of every gate of every flight on which you are booked.
They will re-route your luggage on your new flight. Good luck to you, fellow traveler. Be a volunteer. Sit on your can and make some coins to put toward your next adventure.