You should. Thanks to a crisis in the domestic airline industry, the "new" ticket comes with more restrictions than ever. The non-refundable variety really is non-refundable. You may not be able to collect the kind of frequent flier miles you want. It may not be offered — period on special low-fare deals.

Have your ticket-buying strategies kept up with the changes? If you think of your airline ticket as nothing more than a pass to get on the plane, then they probably haven't. Here are five strategies for saving time — and money — when you buy your next airline flight.

1. Book an e-ticket. In an effort to cut costs, the major airlines have imposed fees on travelers who want to carry honest-to-goodness paper tickets. American Airlines, for example, now charges a $20 fee if you request a pulp ticket. So does Continental Airlines. United Airlines announced that it will stop issuing paper tickets altogether for domestic flights by July 2003 and for all routes where e-tickets are available by January 2004. That worries C. Scott Sheffield, who works for a plastics manufacturer in Fitzgerald, Ga. "I don't feel that I should have to put up with all the uncertainty," he says.

   His concerns are justified. Not so long ago, if you didn't travel with a printout of your itinerary instead of a bona fide ticket, and your flight was delayed or canceled, you might have been out of luck. But new so-called "interlining" agreements between airlines mean that the record of your ticket is easily transferred to another airline. You'll save $20 by going paperless.

   TIP: Remember to bring a record of your trip — either an itinerary or at the very least the alphanumeric "record locator" from your e-ticket — with you to the airport. No technology is perfect.

2. Go "back-to-back." This is one airlines hate, but consumers love. Try buying two discounted round-trip tickets instead of one unrestricted — but more expensive — ticket. You could save hundreds, even thousands of dollars. Use only half of one itinerary and half of the other and then toss the remaining unused segments. It's called "back-to-back" ticketing, and although airlines insist that it's illegal, legal experts like Thomas Dickerson, author of the book "Travel Law", say it is not. "A back-to-back ticket is not illegal. It may be a breach of contract between the airline and the passenger, but it doesn't violate any state or federal laws," he says.

   There is a down side to a back-to-back. United Airlines is cracking down on passengers and the travel agents who help them book these kinds of tickets. British Airways also has reportedly installed new software that follows ticketing offenders. In a letter to travel agents, the British carrier said it would take "appropriate action" in cases where it suffered a loss in revenue from these ticketing tactics.

   TIP: If you book a back-to-back, don't ask your travel agent to do it and don't try to collect frequent-flier miles. If you give an airline your frequent-flier number, it can track your itinerary much easier. In some instances, travelers have been hit with a penalty at the gate for using a back-to-back ticket.

3. Fly like a leisure traveler. Pick the type of ticket you book carefully. If you can afford to stay at your destination over a Saturday night, or can make a reservation two weeks in advance, you'll get a deep discount on your airline ticket. More business travelers are now booking leisure fares, while fewer road warriors are choosing costlier business fares, according to an American Express airfare survey. "Airlines have slashed leisure fares so precipitously, while keeping business fares relatively stable and high, that the fares directed at road warriors are now six times higher than those traditionally targeted at consumers," says Brian Mogler, a vice president for American Express.

   Needless to say, airlines hate the fact that you're refusing to buy these more expensive tickets. That's one of the reasons why carriers such as US Airways recently clamped down on its discounted, non-refundable tickets. Late last summer, the airline shocked the industry when it announced that non-refundable tickets will have no value once the flight has departed. Most of its competitors matched the policy.

   TIP: The discounted tickets come with all kinds of strings attached, such as $100 change fees for alterations made to your itinerary before your flight departs. But think about it — if a new ticket costs less than the change fee, what's the point of paying it? Book a new ticket and throw the old one away.

4. Play the system. Two other ticketing strategies, known as the "open jaw" and "hidden cities" are worth considering. By booking a hidden city ticket, you pay for a less-expensive trip between two airports and get off at a stopover city — which is your intended destination. For example, you may book a round-trip ticket from Baltimore to Tampa, Fla., but only go as far as Philadelphia, the stopover city. (Note that your return trip will be cancelled by the airline, so use this only for a one-way trip. It also means that you can only have carry-on luggage.) An open jaw ticket lets you fly to one city and return from another, often at a considerable savings. For instance, you might fly from New York to San Francisco but return from Los Angeles to New York.

   Note that these tactics don't always yield cheaper prices, nor do airlines appreciate passengers circumventing their pricing scheme. "Airlines are developing the means to catch people who use hidden city itineraries, since you're trying to get around the system," says John Frenaye of Carlson Wagonlit Travel in Annapolis, Md. "So be careful."

   TIP: Don't limit yourself to one airline when trying to book these kinds of tickets. Experienced travelers check with multiple carriers to see which one fits a particular leg of their schedule the best.

5. Don't be held hostage by frequent flier miles. In a previous column, I examined the value — real and perceived — of frequent-flier points. My conclusion: oftentimes, collecting miles isn't worth it. But US Airways' recent announcement that effective next year, miles and segments earned on most non-refundable fares will not count toward its elite-status frequent-flier program, gives us another reason to pause. What that means, basically, is that if you don't pony up the cash for an expensive unrestricted ticket, your chances of becoming an elite frequent flier are zero.

   That's not to say that collecting miles is pointless. But frequent business travelers often book tickets based on how many miles they can collect with a given carrier. A few years ago I remember interviewing confessed mileage-addict Robert Backie, a Phoenix sales manager for a semiconductor equipment company who books extra layovers in order to rack up extra miles on America West Airlines. Now, with mileage awards becoming more restrictive, people like him are undoubtedly wondering if it's all worth it.

   TIP: No-frills airlines like Southwest and JetBlue (which recently unveiled its frequent flier program) offer vastly simplified programs designed to give you free tickets faster. If you've given up on the idea of earning "elite" status, these carriers' frequent flier programs may be a good bet.

Christopher Elliott is the editor of Elliott's E-mail, a free weekly newsletter for travelers. You can e-mail him or visit his Web site.