NEW : Screening procedures enhanced ; more marshals put aboard . NEW : More officers on the scene, and better communication with them. The Transportation Security Administration invoked a `` one hour rule '' after the thwarted attack , which prohibited passengers on international U.S.-bound flights from leaving their seats during the last hour of a flight , sources said . Janet Napolitano says air marshals are assigned randomly . Current , former marshals take exception to Napolitano 's claims .
NEW : Screening procedures enhanced ; more marshals put aboard . NEW : More officers on the scene, and better communication with them. Janet Napolitano says air marshals are assigned randomly . Current , former marshals take exception to Napolitano 's claims .