Thinking of surfing the Internet to get the cheapest airline prices? Look out -- it's tougher than you think.

The USA TODAY newspaper staff spent three weeks airfare shopping on 70 travel industry Web sites. Here's what they found:

The Internet carries a confusing avalanche of cheapest airline prices from booking agents, travel agents and ticket consolidators. Obtaining fare quotes and comparing ticket prices is very time-consuming -- and often frustrating.

Many sites that claim to deliver the cheapest airline prices, don't. They offer fares on many routes that are the same as or higher than those quoted on the phone by airlines and travel agents.

Some Web sites can save a traveler hundreds of dollars for a single round-trip ticket. The best deals can consistently be gotten directly from major U.S. airlines, which each week offer extraordinary Internet bargains on a limited number of routes.

Web sites arm ticket buyers with valuable pricing information that can be used to find the best deal -- on or off the Internet.

USA TODAY's search for a bargain began by typing in the words "cheapest airfares" on CompuServe's Internet search page. Nearly 3 million choices popped up on the computer screen, including Web sites proclaiming "Absolute Cheapest Airfares," "Cheapest and Best Air Fares on the Web," and "For the cheapest flights available over the Internet -- Who're ya gonna call? -- Farebusters."

Using various search engines (such as Yahoo, AltaVista and GoTo), USA TODAY waded through the dizzying array of airfares to obtain fare quotes. At some sites, a quote came rapidly -- within a minute or two. But at others, the process dragged on for 10 minutes or more. Attempts to get quotes were frequently delayed by inability to return to previous screens, error messages, locked cursors and unavailable seats at the prices we selected.

Our frustration often grew after we received the so-called cheapest fare. Was this really the cheapest fare, or could a better one be found on other Web sites or through traditional channels off the Internet? Without the expertise of an impartial arbiter -- a role traditional travel agents are supposed to play -- we didn't have a clue. So we repeatedly had to make time-consuming price comparisons.

The notion that it's easy to go on the Internet and book a flight is a real myth," says Paul Ruden, senior vice president of the American Society of Travel Agents. "For every two bookings on the Internet, there's a phone call made to a human being for assistance."

Lesson 1

Sometimes all you need is the cheapest airline prices.

Many prominent Web sites that say they offer the "best" or "lowest" fares are operated by travel agents, and their fares are often identical or close to those offered by non-Internet travel agents. Fares posted on their Web sites come from the same computer reservations systems used by traditional travel agents.

Germany-based Skytours, which claims it has the "cheapest and best airfares of the Web," quoted USA TODAY in mid-April a $1,091 round-trip fare between Oakland, Calif., and Fairbanks, Alaska. That was $158 more than the least-expensive fare quoted on the telephone by a traditional travel agent, Frank Mangini of New York City-based Pisa Bros.

On other routes, both Lowestfare.com and Skytours offered some prices that were higher and some that were lower than the traditional travel agent. Lowestfare.com is owned by former TWA chairman Carl Icahn and has access to discount tickets on the carrier.

Lesson 2

Consolidators' Web fares are often the same off the Web.

Various other Web sites are run by consolidators, such as Airfare.com, that often offer cheaper fares -- particularly on international routes -- than airline telephone reservationists and traditional travel agents. There's usually no advantage of using the Internet to book these fares because consolidators offer the same prices off the Internet. Consolidators' tickets usually are not refundable, may include other restrictions and earn no frequent-flier miles.

On three routes in late March, USA TODAY requested price quotes on the Internet from Airfare.com, a consolidator, and found better prices than those of a traditional travel agent and airlines' toll-free reservations agents. Airfare.com quoted a $273 round-trip Atlanta-Portland, Ore., fare, on TWA -- $55 cheaper than a travel agent and $35 less than TWA's telephone agent. Between Chicago and Paris, Airfare.com quoted a $438 fare on TWA -- $60 less than the cheapest flight (on American Airlines) offered by the travel agent. Both the travel agent and TWA's telephone reservations agent quoted a $503 fare on TWA.

Lesson 3

Airline sites often best.

Consumers without the patience to hunt through this cyber-Wild West of fares usually can't go wrong by clicking onto major U.S. airlines' Web sites and signing up -- free of charge -- for weekly discount notices. The weekly specials on these sites are often rock bottom -- and usually cheaper than fares offered by consolidators. Drawbacks are that most of the low fares are for last-minute travelers on a limited number of routes and require a Saturday night stay. A change in itinerary also can lead to an expensive penalty.

Last month, United Airlines' E-Fares included a $475 round-trip Seattle-Tokyo ticket. That represented huge savings over the "cheapest" price -- $1,007 -- offered to USA TODAY on the telephone by United's reservations agent. Similarly, United advertised $264 New York-Caracas, Venezuela, tickets on the Internet but $403 on the telephone.

The Internet fares of various other airlines -- including American, Continental, TWA, Southwest and Alaska -- also provide big savings over their published fares.

"There are opportunities to get good deals on the Internet -- just like inventory clearances at department stores," Ruden says.

The number of routes with cheap Internet fares varies weekly at each airline. Alaska Airlines, for example, offered Internet discounts on 28 routes during the last week of March, on 22 routes the following week and on 26 routes the next week.

Lesson 4

Southwest offers fare specials you can plan around.

Unlike many of its competitors, Airfare.com Southwest Airlines offers Internet specials that are not just for last-minute travelers. On April 14, for example, the carrier posted a one-day sale that allowed on-line customers to purchase bargain tickets valid for travel on 37 routes from May 4 through Sept. 6. The deals included such attractive round-trip fares as $116 for Oakland-Tucson, Ariz.; $66 for Phoenix-El Paso; and $60 for Cleveland-Baltimore-Washington.

Some airlines, however, are posting Internet fares that are the same as those available from telephone reservations personnel and traditional travel agents. Last month Virgin Atlantic touted its on-line "sale fares to London." The round-trip fares -- which included Miami-London for $271 and Los Angeles-London for $350 -- were low, but they were identical to the prices we received when we called Virgin Atlantic's toll-free reservations number.

Lesson 5

Internet information is power.

Regardless of whether you actually buy a ticket on line, information that can steer you to the best fare is readily available on the Internet. At Bestfares.com, for example, hundreds of listings and news stories reveal the latest discount deals, as well as past prices in particular markets.

Swissair's Web site recently posted "special offers," including a $409 New York-Zurich round-trip fare. We then checked the fare for the same flight on Swissair's toll-free reservations line and were told the cheapest fare was "a special sale promotion -- $739" round trip. When we told the agent about the cheaper fare on the Internet, the agent hunted for the fare and offered a $409 round-trip ticket leaving from Newark (N.J.) International Airport.

If you're determined to put up with the aggravations, though, and have the time to seek that ever-elusive "cheapest" price, Bestfares.com Editor Tom Parsons has some advice. "The Internet gives you a place to do research, but don't take everything as gospel," he cautions. "Don't think it's the cheapest airline price -- even if it says so. People can spend days on their computer and still not come up with the cheapest fares."