Izhar Cohen The company behind the technology says upgrade auctions may soon come to the U.S. So far, airlines say travelers end up spending more for upgrades in online auctions than they would spend at check-in. Unlike a casual offer at an airport kiosk, the auction system can generate excitement as fliers strategize about how to win."You can buy the cheapest ticket and still have a chance of sitting in business class," said Danny Saadon, North America vice president for El Al Airlines, where the average winning bid for a business-class upgrade is $800. That's a deal when the airline's business-class tickets <a href="http://www.cnjy.dfyse.com/forum.php?mod=viewthread&amp;tid=113966" rel="nofollow">in Las Vegas as part of an 11-city press tour #yva93</a>    cost anywhere from $3,000 to $10,000 more than coach. El Al, of Israel, has also started auctioning off empty middle seats on flights to and from Israel for coach passengers in adjacent seats who want more space and don't want a potentially large neighbor. Reserving an empty middle seat goes for about an extra $150, Mr. Saadon said. "When you have an empty seat next to  <a href="http://www.coach-outlet-storeonline.com/" rel="nofollow">Coach Factory Outlet</a>   you, everything is OK," he said. "The food tastes better. You are ready to forgive everything."El Al is one of 10 airlines using the Plusgrade system. Others include Virgin Atlantic, Air New Zealand,  Panama's Copa Airlines, United Arab Emirates' Etihad Airways and TAP Portugal. Austrian Airlines, a unit of Germany's Lufthansa,  signed on last week.Instead of offering last-minute upgrades at a set price, "we ask the customer, what are you willing to pay?" said Ken Harris, chief executive of Plusgrade, the New York City company that developed the system. "No one ever complained they got an upgrade, especially at a price they set."Mr. Harris says Plusgrade is likely to launch with an airline based in North America this year. "It's in progress," he said, declining to identify the carrier.Midweek flights typically have lower demand for business class, and so more opportunity for auctions. Carriers can select which customers to invite??ome open the bidding to all passengers, others limit it to higher-fare levels. They can target passengers according to their profile, such as those who might be candidates to buy business-class seats in the future, or who fly in business class when their company pays.Frequent fliers with top-tier status and easy access to upgrades are already complaining that auctions have eroded their a <a href="http://www.coach-outlet-storeonline.com/" rel="nofollow">Coach Factory Outlet Online</a>   bility to snag cushy seats.Airlines holding the auctions say they take care of elite-level frequent fliers by processing their upgrades before awarding seats to auction bidders.Air New Zealand, which began offering "OneUp" upgrade auctions last July, says it has seen a high level of repeat bidders on subsequent flights. "They like the idea of being able to make an offer at a level they feel they can afford," said Mark Street, the airline's head of customer loyalty. "More customers are enjoying our premium cabins, and we're getting more revenue." Upgrades typically move passengers to the next class of service. On an airline with a "premium economy" cabin, like Air New Zealand, coach customers bid to upgrade to premium economy and premium-economy passengers to business class.Dan Arcari, a software engineer moving back to the U.S. from New Zealand, tried several auctions without success. He has put together a database on FlyerTalk.com of 110 winning bids on Air New Zealand, tracking routes and prices shared by travelers. Still, bidders in the auctions don't get a clear idea of how many travelers they are competing against, or how many seats they're fighting for. Airlines guard that data vigilantly."It's a giant mystery box," said Mr. Arcari. "You just don't know what's going to happen." Executives from Air New Zealand and other airlines sa <a href="http://www.coach-outlet-storeonline.com/" rel="nofollow">Coach Outlet Store</a>   y participation in auctions is growing.Mr. Acari was determined to score an upgrade to a premium-economy seat on an Auckland-to-Los Angeles flight for his wife, who is pregnant, but his bid of $390 was rejected. Seats were still available, though, and Mr. Arcari paid about $750 in additional airfare for a premium-economy ticket.Despite the desirability of lie-flat beds, entertainment and fancy-meal service in business class, there are lots of empty seats to auction off. Airlines historically have been loath to deeply discount business class, despite occasional sales during soft travel periods, because many business travelers make plans on short notice. Business travelers are also willing to pay for comfort and space to work so that they reach their destination rested and relaxed. Airlines figure it's better to fly some empty seats than discount the entire premium cabin.Demand for first class and business class typically follows business confidence, according to the International Air Transport Association, which publishes a monthly premium traffic report. The front cabins of airplanes haven't yet seen a strong return in demand since the recession. In February, the most recent month reported, the number of passengers in premium seats on international routes was just 1.2% higher than a year ago, while economy passengers were up 3.7%, the association said. Matt McKevitt, a consultant and frequent traveler, who until recently lived in Napier, New Zealand, successfully bid for upgrades on two vacation trips, one to Tonga and the <a href="http://www.coach-outlet-storeonline.com/" rel="nofollow">Coach Factory Online</a>    other to Melbourne, Australia, where he now lives. Each cost less than about $168 on top of the coach ticket price of about $504. Because he is a top-tier frequent flier, Air New Zealand automatically increases his bid by 50% at no charge. With his status he could have paid a fixed price of about $210 for an upgrade, but figured those vacation trips would have light business-class bookings, giving him a good chance of getting the upgrades for less.He was happy with both bids but figures the odds of satisfaction would be much lower on longer flights. "To have a reasonable chance of an upgrade going through I would have to pay a lot more for the bid," he said.El Al began a pilot program of business-class auctions in May 2012 and a few months later launched the program in full, Mr. Saadon said. The empty middle seat auctioning began in September.Once you have booked a ticket on the El Al's website, a pop-up message tells you if an upgrade auction is available. "Many people do it months in advance and forget. Then they get a phone call or email telling them they won," Mr. Saadon said. El Al has seen cases in which friends traveling together bid against each other to see who can win the auction. "It's like gambling," he said. "It adds excitement."A version of this article appeared April 25, 2013, on page D1 in the U.S. edition of The Wall Street Journal, with the headline: Flier Auctions: Better Seats, Going Once, Going Twice ....