According to The Register, the airlines are planning to use mobile phones to cut costs and to sell ad revenue. As you book a flight, you will give your mobile phone number to the airline. They will use this to push information on the flight to you (not so bad), and once you get to the airport, they may even check you in electronically via your phone, which is already underway in Japan. What could get ugly is the the notion that they could also push ads to your phone once you get in the airport, so the idea is that you'll pay a fortune for a a cramped seat and then get spammed at the same time. If you have flown recently, you may have noticed some airlines have put ads on the seat back trays, so as you "enjoy" your free beverage (snacks seem to be out completely now on some airlines) you get to read the ad on the surface of the tray.