Now playing on United Airlines' seatback screens: personalized ads. The platform is the latest example of airlines trying to drum up new lines of revenue and leverage their lucrative loyalty programs. Delta Air Lines said in early 2023 that it would start offering free Wi-Fi to customers if they were registered members of its SkyMiles frequent flyer program. Customers can opt out of seeing targeted ads through a United web page, and United says advertisers can't access customers' personally identifiable inf ...