Amazon said in a message on its homepage on Monday that it was running a one-day, 15-percent-off sale for its new line of Kindles to celebrate the Federal Aviation Administration’s recent reversal of a longtime policy that banned airplane passengers from using electronic devices during takeoff and landing. Nick Bilton, the New York Times journalist who had pushed for the change, received a shout-out from Jeff Bezos in the prepared remarks for Amazon’s third-quarter earnings report.