Airplane tray tables may soon get smarter, allowing travelers to plug personal tablets directly into the in-flight entertainment system or Wi-Fi, potentially opening another channel for advertisers to target ads based on what passengers watch.
Smart Tray International, which makes airline tray tables that let tablets share cramped seatback space with snacks and other items, has teamed up with Clear Channel Airports to add in-flight digital advertising to its arsenal of services.
"Airlines are always looking for ancillary revenue and often subcontract generating some of that revenue to other companies," Smart Tray CEO Nick Pajic said in an interview.
"Now that passengers may use their personal electronic devices gate-to-gate, our company can provide a device that makes it easier to use tablets, while Clear Channel can generate advertising" that creates shared revenue when the devices are plugged into the on-board network, he added.
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In-air advertising is a growing market. RMG Networks, which runs RMG Airline Media, estimates the current market for air travel advertising at $300 million.
"In particular, we've seen a tremendous leap in advertiser interest around in-flight digital campaigns," RMG CEO Garry McGuire said via email. "We expect growth to be driven by advertiser demand and ... inventory as more carriers upgrade their fleets and install Wi-Fi and digital seatback entertainment systems."
The Smart Tray company makes three models: The X1 and X2 have tablet holders allowing passengers to watch their own material or connect to Wi-Fi; the X3 works with an airline's in-flight entertainment system for preloaded or streamed content.
When passengers connect devices to the in-flight entertainment system or Wi-Fi network "the airlines may be able know how many people watch the advertising—and for how long," Pajic said. "The technology could deliver a personalized ad on a seat-by-seat basis, but that's not how we're intending to do this."
The initial plan is to analyze data shared by airlines to let advertisers know how successful their campaign has been, said Jason King, a spokesman for Clear Channel Outdoor Holdings, the parent company of Clear Channel Airports. They could do more with the information later, however, he said.
"Clear Channel Airports and Smart Tray can anonymously utilize passenger data to 'potentially' deliver relevant messaging to travelers based on individual preference," King said in an email.
Smart Tray and Clear Channel haven't signed up any airline customers yet, according to Pajic, but but negotiations are underway with several carriers.
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Raymond Kollau of Airlinetrends.com warned that tracking passengers' online behavior and using that data for commercial purposes can backfire.
"In 2012 it was revealed that British Airways Googled VIP passengers before their flight in order to recognize them personally when they boarded," he said. "For British Airways this was just a little gesture to make its service more personal, but it became a big privacy debate, even though similar practices have been adopted by boutique hotels around the world for years."
Though advertisers likely will steer clear of highly personalized digital in-flight messages initially, surveys show that "passengers and consumers in general are now willing to give up certain privacy rights in order to have an enhanced or a more relevant experience," said Dan Thompson, vice president of marketing and communications for GuestLogix, an in-flight retail technology company.
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If Smart Tray and Clear Channel can "crack that code and walk that line between not invading privacy and instead providing an experience that adds to the enjoyment of a trip, airlines will embrace that," he said. "Especially if there's an upside from the revenue perspective."
—By Harriet Baskas, special to CNBC.com. Baskas is the author of seven books, including "Hidden Treasures: What Museums Can't or Won't Show You," and the Stuck at the Airport blog. Follow her on Twitter at @hbaskas. Follow Road Warrior at @CNBCtravel.