'Hacker Fares' pair one-way flights for savings

A search for a round-trip Boston-to-Seattle itinerary on Kayak.com in early October, for example, returned a Hacker Fare with a US Airways flight to Seattle and a JetBlue return flight for $353, shaving $11 off a traditional, one-airline itinerary.

Kayak says it grabs available one-way fares from a variety of sources, including airlines and online travel agency sites. Kayak displays these one-way fares in a round-trip itinerary as a Hacker Fare when it produces the lowest fare for a city pair in general or the cheapest in a time slot, adds an airline or saves time.

The attention-getting Hacker Fare name is meant to conjure images of a "hacker" manually cobbling together two one-way fares into an unorthodox itinerary and beating the airlines at their own pricing game.

Although Kayak drew attention with its recent introduction of Hacker Fares, the U.K.-based Skyscanner has been offering a similar service on its U.S. domain, Skyscanner.com, since its debut in 2009.

Kayak's Hacker Fares and what Skyscanner terms "airline combinations" are known as split tickets in airline parlance.

Split tickets can differ from other itinerary types on travel websites. "Mixed itineraries" (one airline outbound and another inbound) and interline itineraries or alliance fares (where two airlines team and you connect from one to the other, largely for international flights) all require agreements between the airlines.

However, split tickets don't need itinerary agreements between the airlines so Kayak's Hacker Fares and Skyscanner's airline combinations provide flight pairings that would require considerable effort to compile yourself.

Still, there are some caveats:

•Kayak and Skyscanner are travel metasearch sites and don't process flight bookings. You have to book at an airline or online travel agency website.

•Split tickets add complexities to the flight-purchase process because for a round trip you must complete separate bookings on different websites: one for each one-way flight.

Kayak and Skyscanner caution you to open both booking windows for the separate flights and verify that both are actually available before completing the two bookings. But there are no guarantees that both flights will be available. If you can book one and are unsuccessful in booking the second, that can leave you hustling to, well, "rehack" your flights.

The great thing about split tickets is that they provide new flight options, whether they offer a cheaper fare or additional airline choices, or merely spare you from a three-hour layover.

The Skyscanner and Kayak split-ticket services automate an online process that previously had to be done manually with considerable research.

But, as both Kayak and Skyscanner acknowledge, split tickets don't always provide the cheapest options, if price is your Holy Grail. Other mixed itineraries or even routine round-trip itineraries on other airlines may have a cost advantage.

In a limited number of tests on domestic routes, Skyscanner often retrieved lower-cost round-trip itineraries using airline combinations, mixed itineraries or traditional round trips than Kayak's Hacker Fares.

Skyscanner's Mary Porter says the site can show cheaper prices because it searches many sites, including two that Kayak doesn't: CheapOair.com and SmartFares.com.

Meanwhile, Kayak's Robert Birge says a larger search sample might show different results, and Kayak's "accuracy technology" helps ensure "the flights are actually available at the prices presented." That is, Kayak may strip out lower fares if they are unavailable.

Finally, if split tickets sound appealing, but you are concerned that parts of your split ticket may be sold out when you hit the "submit" button, consider using a travel agent.

Travel agents have been offering split tickets for years. They can eliminate the risk to the traveler if one of the flights turns up unavailable, because they would merely book a different itinerary.

However, travel agents may not have access to all the lowest fares, because some low-cost carriers don't participate in their reservations systems, and even when they do, these airlines may not provide all of their lowest fares to agents. Also, a travel agent would likely charge you a service fee.