How to Beat Airline Fees

En espanol | The airlines' strategy to extract every last penny from you is paying off…big-time! In the second quarter of 2010, U.S. airlines raked in $2.1 billion in "ancillary revenue," up 13 percent from the first quarter.

Many fees are cleverly hidden. Want to board early or sit in the exit row? Or book a ticket over the phone or in person rather than online? Even get a pillow and blanket? It could cost you.

See also: 9 travel facts you must know.

A lot of these fees are embedded in the online booking process. Sometimes you have to click on a box to refuse an offer. Even worse, an optional charge will pop up on the screen at the airport check-in kiosk — right when you're in a hurry. My rule of thumb: Any time an airline offers you a service, ask, "Is this going to cost me?"

Send your bags ahead

The biggest source of the airlines' extra revenue comes from baggage fees. Airlines collected $893 million in baggage fees in the second quarter of 2010. Here's a secret: I haven't checked a bag on a domestic flight in more than a decade. Instead, I ship my luggage from home. Some airlines charge upward of $60 for two suitcases, but you can ship a 30-pound bag cross-country using FedEx Ground or UPS Ground for $26 to $41. In some cases it could end up costing you a bit more, but the extra value is priceless: door-to-door service, no schlepping, no waiting around carousels — and no paying the airlines to lose your luggage.

Check your bag (for free!)

Here's a neat guerrilla tactic: As more and more passengers roll their suitcases onboard to avoid fees — filling the overhead bins and slowing down the boarding process as a result — gate agents have begun asking if passengers want to check their carry-on bags…for free. Don't wait. Walk up to the gate agent and ask if he or she would like to check your carry-on bag. You won't see that suitcase again until baggage claim at your destination.

Next: How to avoid fare-change fees. >>