By streaming content over wireless systems, passengers will have a wider array of contentbr and the carriers will not have to maintain screens because passengers will bring their own portable devices on board.br By the time next-generation planes are in service, the technology on them will already headed for obsolescence, Jason Rabinowitz,br the director of airline research for Routehappy — which among other things, tracks in-flight amenities — said in an interview.br Another financial incentive: Without the screens, carriers can install slimmer seats, which means they can accommodate more passengersbr and earn more money, Brett Snyder, the author of the airline industry blog “Cranky Flier,” said in an interview.br Mr. Hoppe noted that carriers like Southwest Airlines had been promoting streaming content for eight yearsbr and had never purchased planes with seat-back screens.br “The thing with the airline industry is nothing happens quickly,” Mr. Rabinowitz said.br “Rise of in-flight Wi-Fi aside, the zero screen purchases made by Southwest aligns with the factbr that many of the carrier’s flights are shorter in duration than the time it takes to finish a movie,” he saidbr Those seat-back screens that have long been part of in-flight entertainment systems are preparing to depart from many airplanes, experts say,br and will gradually be replaced by content streamed to passengers’ electronic devices through improved wireless service.