NEW YORK (CNN/Money) - You want to get away and you don't care where. Well, we've got some deals for you. But you have to be able to hang loose and act quickly, virtues that more and more travelers seem to be acquiring.

Jane Glennon, a spokeswoman for travel publisher Fodor's, says the company's data show that, "Where once people planned three to four months before they left, that average is now six weeks."

Amy Ziff, editor-at-large for Travelocity, agrees that "last–minute" travel -- which she defines as anywhere from two weeks to three hours before the plane leaves -- "has exploded." Her customer surveys have shown that many Americans are planning one long trip a year and a series of short ones. While travelers usually book their long annual vacations in advance, their short trips can have much shorter lead times.

Driving this trend are E-Savers and other specials from airlines from Internet travel agents that offer deeply discounted fares that must usually be booked at the last minute. Now, what would once have been regarded as poor planning can save you plenty.

Mark and Caroline Gabriel shopped the Net for weeks, looking for a low-priced week at a Mexican resort, but the best price they found, $3,000, strained their budget. The day before their week off began, Mark found the exact same trip, an all-inclusive vacation package from Houston to Cozumel, for $1,500.

Other examples found on the Internet this week: Fly United Airlines from New York to Hong Kong for $665 round trip (compared with the airline's next lowest price of $1,193); book a US Air flight to Boston from St Louis for a long weekend, $158 compared with a normal restricted fare of $350; fly Aeromexico from Los Angeles to Puerto Vallarta for up to two weeks in August, only $175, half the normal price of $350.

Last-minute savings Sometimes it pays not to plan ahead. But remember, while deals like this are great, you can't count on them. Trip  Booked in advance  Last-minute price  L.A. to Puerto Vallarta  $350  $175  Boston to St. Louis  $292  $158  2 nights in Las Vegas  $113  $83  Alaskan cruise  $1,579  $559   * See story for details

Interested? Here's what you do: Register for specials on the Web sites of airlines that serve your hometown area. Then, every Tuesday or Wednesday, depending on the airline, you'll receive e-mails advertising various deals. Often they require customers to leave by the following Friday or Saturday and return on Monday or Tuesday, but there are many that allow for stays of a week or more and that you can book a week or more in advance.

In addition to notifying customers via e-mail, airlines make listings of great last-minute deals available on Travelocity, Expedia, SmarterLiving, and other Web travel agents. Travelers can search these sites for destinations all around the country, and internationally as well. The keys to taking advantage of the savings are flexibility -- you have to be able to take off at the drop of a hat -- and decisiveness -- you have to make up your mind before the seats get sold out.

Travelers increasingly go to these Web sites to combine the low airfares with do-it-yourself package deals in which they can pick and choose among car rentals and/or hotel rooms to custom-make one low-priced package. "It's a great way to take advantage of the savings made available by airlines, hotels, and car rental companies," says Travelocity's Ziff.

Pre-packaged deals can be stunners. Through Southwest Airlines you can book a two-night stay in Las Vegas for $83 double occupancy, including airfare from Los Angeles. Rooms at the hotel usually start at $59 a night and the promotional price for a ticket from LA is $54, meaning the package takes 26 percent off an already discounted price of $113. Or take a Holland America cruise to Anchorage for $559, which is 65 percent off the regular price of $1,579.

Teri Franklin, product manager for Expedia, says that her customers save 30 percent on a typical package. Expedia's 2002 package-sales revenue shot up 305 percent compared with 2001.