Airlines are hiking and levying fees like mad. Knowing the new policies can save you a bundle

In recent months, airlines have levied a slew of new charges—and the trend is expected to continue, says Ray Neidl, an industry analyst at Blaylock & Partners. "Airline service is becoming more spartan, and if customers want something, they are going to have to pay for it."

For starters, most carriers have raised the fees for their unaccompanied-minor programs to a minimum of $80 per round-trip. Not only that, they now require children 14 and under traveling without an adult to use the service (the age ceiling had been 11). Worse still are the charges you may not know about in time to avoid them. Take the new luggage rules: Once, any piece of luggage under 70 pounds could be checked for free; now, if it tips the scales at 50 pounds, you pay $25, and $50 (even more on some lines) if it exceeds 70. You'll also get fined for a single over-the-limit bag even if your total weight for the two bags allowed on board comes in under 100 pounds.

And in an effort to cut their annual $2 billion food tab, many airlines now charge for meals. On domestic flights, be prepared to dole out $7 for "breakfast," usually a croissant or yogurt, and $10 for a salad or a wrap. American, America West, United, US Airways, and Delta—and its low-fare subsidiary, Song—are all experimenting with food sales. Even Midwest now asks passengers on some flights to pay for the classy cuisine that earned the carrier its reputation.

Among the biggest annoyances are the ever-changing rules regarding nonrefundable tickets. Big airlines recently retreated from their "use it or lose it" policies on discount fares, whereby the entire value of a ticket was forfeited if a passenger failed to cancel or rebook on or before the date of departure. Under new rules adopted last fall, most carriers will now let you keep a ticket for a year, provided you pay a $100 penalty (between $150 and $200 on international itineraries) and any difference in fare.

But here the gap between the majors and the low-fare lines is striking: Most discount lines still hew to more generous limits on bags and unaccompanied children, and Southwest doesn't charge you to change your ticket. The major carriers justify their higher fees as reflecting the greater complexity of their fare structures, but that argument doesn't always hold up. If you fly from New York to Long Beach, California, for example, American will dun you only $25 if you change your ticket, $75 less than if you flew to nearby LAX. Why the disparity? Long Beach just happens to be the West Coast fief of low-fare champ JetBlue, which charges $25 for all itinerary changes. "Airlines are just driving fliers into the arms of the low-cost carriers," says Kevin Mitchell, head of the Business Travel Coalition. Still, there are some very good fares to be had on the majors, he notes, as long as you know the pitfalls in advance.

Ticker Tape: The first flight attendants, in the 1930s, were required to be unmarried nurses and to weigh under 115 pounds.