Airline passengers, whether traveling for business or pleasure, might want to think twice about how much they bring along for the ride starting next month.

Five of the seven major US airlines (Continental, Delta, Northwest, United, and US Air) plan to start charging most customers $25 each way to check a second bag starting May 5. Only American and Southwest, of the largest carriers, have decided not to go along—for now. Airtran is adding a $10 second bag fee for travel on or after May 15. Spirit Airlines already had a $10 fee if paid online, or $20 at the airport. But why let the airlines overcharge you for a service they provide so poorly? After all, lost, damaged and stolen luggage is a bad situation getting worse. If you're traveling domestically, read on for a better solution.

Q: Do you have to pay these fees even if you’ve spent $3000 on a first class ticket?

A: No. The new fees do not apply to all passengers. Those buying first class or business class tickets, or flying on frequent flyer awards in those classes, will typically be exempt, as will frequent flyer program members who have achieved upper tiers with their airlines (such as United Mileage Plus Premier customers). Military personnel flying “with orders” are also exempt.

Q: Why are the airlines adding these fees?

A: The cost of jet fuel is skyrocketing, yet the airlines have not been able to raise fares to compensate. So they’re adding and increasing “ancillary” fees. All sorts of fees are going up, such as those for pets carried in the cabin and re-depositing unused frequent flyer miles.

Q: What if you’re carrying more than two bags? Are those $25 extra each as well?

A: We could only wish. These fees are in addition to existing ones for excess, oversized and overweight bags, which have also been increased recently. So a passenger traveling on United with three checked bags weighing 50 pounds or less will be charged $25 for the second but $100 for the third. If any of the three bags tips the scale at 51 pounds more, however, overweight charges of an additional $100 per bag, each way, kick in. So unless otherwise exempt, a passenger flying roundtrip on United with three bags weighing just a pound over the 50 pound limit would be charged $200 for the first ($100 overweight fee each way), $250 for the second (second bag fee of $25 times two plus overweight fee of $100 times two), and $400 for the third (a $100 third bag fee times two plus a $100 overweight fee times two), for a total—fasten your seat belts—of $850.

Keep in mind that these are domestic fees, and international charges may be higher, depending on destination.

Q: $850? ! That’s more than most fares. So what’s a traveler to do?

A: There must be a better way, and there is: UPS, US Postal Service, or FedEx. Flying from your home in Manhattan to a convention in Long Beach? UPS will send your 51 pounds of trade show samples each way for $59.34, when last checked at ups.com, with four-day service.  Or ship that 60 pound suitcase from Miami to San Francisco for $63.78 each way. Not only will you avoid having to lug your luggage through endless airport concourses, but chances are that UPS will do a better job of not losing your shipment than your airline will (and if they do misplace it, they’ll at least feel bad about it). 

Q: And speaking of lost luggage, airlines don’t take responsibility for many types of items lost or damaged in checked luggage, or for carryon luggage.  What’s excluded?

Read the fine print in your airline’s lost and damaged luggage policy: those items are not covered if something goes amiss. They’re in the same category as cash, valuables, jewelry, and electronics. At least when you ship FedEx or UPS, you can declare a higher value and insure your business items. In fact, before you pack for your next flight, it’s a good idea to have a look at what your airline will not take responsibility for should your checked bags be lost or damaged. Here’s American’s list, for example, which is pretty standard for the industry:

“ Antiques, artifacts, artwork, books and documents, china, computers and other electronic equipment, computer software, fragile items (including child/infant restraint devices such as strollers and car seats), eyeglasses, prescription sunglasses, non-prescription sunglasses and all other eyewear and eye/vision devices whether lenses are glass, plastic, or some other material, furs, heirlooms, items carried in the passenger compartment of the aircraft, liquids, medicines, money, perishable items, photographic, video and optical equipment, precious metals, stones or jewelry, securities and negotiable papers, silverware, samples, unique or irreplaceable items or any other similar valuable items.” (Note the “samples” bit, all you road warriors). United excludes these items as well, and also mentions “business effects” in its disclaimer -- which probably includes your press kits and all those fridge magnets you were going to give away at the trade show.

So tell your airline no thanks next time they try to hit you with baggage fees. Plan ahead, tell your hotel (or branch office or family) that you’re expecting a shipment and to hold it until your arrival, and save yourself some money and a backache.