Most of us meekly accept an airline’s offer of a voucher for future travel. We’re entitled to more.

Let’s begin with the fact that if you’re scheduled to fly in the United States, your chances of getting bumped are greater than ever. The practice of bumping jumped 40% in the second quarter of 2009, and it’s expected to get worse as airlines cut back on flights and try to pack every airplane with as many passengers as possible — sometimes more than is possible.

Typically, if you’re bumped, the airline offers you a voucher toward the cost of a future flight. That’s usually a bad deal. Such vouchers often have tight restrictions, such as blackout dates or lack of eligibility on discount fares. (Personal experience: I once received a voucher for a first-class upgrade. The restrictions: It was good only on a full-fare coach ticket and had a shelf life of just one year. You know how many fares are classified as “full fare”? Very, very few.)

So let’s say you don’t want, or are wary of, a voucher. U.S. Department of Transportation rules say you have the right to demand cash instead, to be paid on the spot.  Most travel experts say taking the cash is a better deal for you.

What’re the odds?
What are the chances you’ll get bumped? That depends on which airlines you fly, according to data from the U.S. DOT. Here’s a list of carriers, descending from most likely to bump to least likely:

• US Airways
• United
• Alaska
• Southwest
• Delta
• American
• AirTran
• JetBlue

The U.S. DOT has a host of rules — many of them new — on how much you’re entitled to and under what circumstances. To see a summary of the rules, go to the U.S. DOT’s aviation consumer protection page and click on “Overbooking.”