Updated on December 18, 2007.

THESE DAYS AIRLINES are desperate to raise revenues without raising fares. One solution? Tack on some fees.

"The airlines are getting more into the nickel-and-dime mentality, exploring every angle to bring in incremental income," says Tom Parsons, CEO of BestFares.com. Competition from low-cost carriers makes it tough for major airlines to increase fares, he says, so they make up the difference in fine-print fees. Here are 10 to watch out for:

1. Booking Fees

Potential cost: $5 to $25

"The most prevalent sneaky fee is a booking charge of $10 to $25 if you want to make a reservation any way but through the airline's web site," says Ed Perkins, a contributing editor for

. If you call the airline, most charge you at least $15 per ticket for phone reservations. Third-party travel sites charge these fees, too: Expect to pay $5 to $15 per ticket on sites like Expedia, Orbitz and Travelocity for securing your reservation.

Solution: Use travel comparison and booking sites to shop around, but make your arrangements through the airline's web site. It's the only fee-free way to book.

2. Change-of-Plans Fees

Potential cost: $25 and up

"Be sure of your plans if you're really going for the low-fare price," cautions David Lytle, editorial director for

. The cheapest fare classes are nonrefundable and can't be changed at all. Even if you pay more upfront for a refundable fare, you're still subject to hefty change fees. Most airlines charge a flat fee, plus the difference in fares on your old and new travel dates. Discount tickets purchased through third-party travel sites and travel agents carry even bigger penalties. Delta, for example, regularly charges $50 to change your flight. If you didn't buy your ticket through Delta.com, or over the phone through one of its agents, the airline charges another $10 to $15 to change your reservation, plus the fare difference.

Looking to change your reservation by just an hour or two? Expect to pay for that, too. Continental and Northwest both charge a $25 fee to allow passengers to get a confirmed standby seat on an earlier flight.

Solution: If there's a chance your plans may change, look into the airline's policy before you book. Paying a little more for your ticket through the airline's own site instead of a third-party site can save you in the long run should you need to switch flight times or dates, says Lytle. For standby seats, your best bet is to show up early and ask. This standard standby route is still fee-free.

3. Airport Improvement Fees

Potential cost: $4.50 to $160

Now that Chicago has approved O'Hare International Airport's new runway, its travelers can expect an additional $4.50 charge per airline ticket to fund construction. These so-called passenger facility charges aren't uncommon, though the Federal Aviation Administration regulates them carefully, says Perkins. International flights are worse. In January, the U.K. doubled its Air Passenger Duty, taxing consumers for the greenhouse-gas emissions created by flights entering or leaving the country. For coach passengers, the new fee is $80, while first-class passengers pay $160.

Solution: If you can, divert your trip to an airport (or country) where the tax is less expensive, says Perkins. For domestic flights, check the FAA's PFC database.

4. Pick-Your-Seat Fees

Potential cost: $15 to $299

When flying coach, there are two givens in the seat selection game, says Parsons: Nobody wants the middle, and everyone wants extra legroom. United charges $299 annually for an Economy Plus subscription, which gets you and a traveling companion seats with five inches of extra legroom whenever available. On Northwest, booking an exit-row seat costs $15 extra, while American charges consumers who didn't book directly through the airline a $15 fee to change their seats.

Solution: Look before you book to see if your airline charges a fee for specific seats. Already booked? Wait until you're at the gate, and then ask nicely if there are open exit-row (window/aisle) seats, suggests Parsons. That late in the game, it's the gate agents' discretion to seat you and they probably won't charge.

5. Curb-Side Check-In Fees

Potential cost: $2 per bag, plus tip

Handing over your luggage prematurely can cost you, depending on your airline and departure airport. Alaska Airlines, Northwest and United all charge $2 per bag (plus tip) for curb-side baggage check-in at major hubs.

Solution: Ask about a charge before you hand over your bags. Or haul your luggage another hundred feet or so to the counter inside.

6. Baggage Fees

Potential cost: $25 to $100 for an overweight bag; $10 to $80 per piece of luggage beyond an airline's checked-bag limit.

As fuel prices increase, weight-watching airlines are pushing even more penalties on overpacking passengers. In June, Spirit Airlines started charging $10 per checked bag; $5 if you make arrangements in advance online. As of September, British Airways stopped accepting bags weighing more than 51 pounds.

A year or two ago, most airlines wouldn't have bothered charging you for a bag that was slightly overweight, says Parsons. No more. "They look for overweight luggage like there's no tomorrow," he says. "If you're even one pound over, you're going to get slapped with a $25 fee."

Solution: There are plenty of ways to keep your bags below the 50-pound limit for most domestic flights. For tips, and the baggage policies of major U.S. airlines, click here.

7. Paper Ticket Fees

Potential cost: $50 to $75

"Paper tickets are on the way out," says Lytle. "It's one of the easiest ways for airlines to cut costs." Expect to pay big if you insist the airline mail you paper boarding passes. United asks consumers to cough up an extra $75 per paper ticket, while American, Continental, Northwest and U.S. Airways each tack on $50.

Solution: E-tickets are a simple solution, even for consumers who aren't Internet-savvy, says Lytle. (Just check in at the airline's e-ticket airport kiosks, and you'll get a printout boarding pass, free of charge.)

8. In-Flight Amenities Fees

Potential cost: $1 to $5

After the airport hassle, all you want to do is prop your head against a soft pillow, drown out the noise with some decent headphones and relax with a cold drink and a snack. OK, but it'll cost you. Air Canada charges $2 for a "comfort kit" of pillow and blanket. JetBlue tacks on $2 to upgrade your complimentary pair of headphones. Spirit charges $1 for sodas and coffee, while United offers a $5 snack box.

Solution: Don't depend on the airline to make you comfortable, says Lytle. Invest in your own inflatable pillow and headphones. Bring snacks from home, keeping new security restrictions in mind. "You can bring food items that aren't gel through security," he says. "Yogurt is suspect, but a cheese sandwich is fine."

9. Fuel Fees

Potential cost: $14 to $70

As fuel prices rise, you won't just feel pain at the pump. Airlines are passing along their increased fuel costs. In May, British Airways hiked its fuel surcharges by $6, to $70 for flights longer than nine hours, and $66 for shorter flights. Air France followed suit, announcing it would double its fuel surcharge (to $13.53 per segment) until the price of oil drops below $65 per barrel for 30 consecutive days.

Solution: Compare prices for your international flight on the airline's U.S. site, says Perkins. "Airlines are required, per U.S. Department of Transportation regulations, to include any fuel surcharges in the base price," he explains. While you won't avoid the fee, you can gauge its effect on your ticket price from the outset and shop accordingly.

10. Redeeming Freebies Fees

Potential cost: $15 to $300

Got miles or a voucher to redeem? Better have your wallet on hand, too, says Tim Winship, publisher of

. "Airlines have effectively taken the 'free' out of 'free ticket' with booking and redemption fees," he says. Northwest Airlines charges $50 for last-minute reward ticket redemptions, while American Airlines tacks on a $150 to $300 surcharge when consumers use miles to upgrade a coach ticket they purchased for less than the full fare.

Even sneakier, reward travel can rarely be booked online and vouchers never can, says Winship. "You're forced outright to pick up the phone and call in to an agent for help," he says. Then you're right back to Fee No. 1: A $15 to $25 charge from most airlines for booking over the phone.

Solution: Read the fee fine print before you book reward travel to ensure you're getting your money's worth out of those miles, says Winship. The longer your trip, and the more expensive the ticket would be, the more value your miles have even with an attached fee.