Ben Sliney, a former air traffic controller and lawyer who had rejoined the Federal Aviation Administration in 2001, was thrust into one of the most consequential roles in American history on his very first day as national operations manager: 11 September 2001. His job was to oversee the flow of air traffic across the entire United States, and within hours of starting he had to manage the unfolding terrorist attacks, ultimately making the unprecedented decision to ground all flights in US airspace.

Sliney had a long and winding career path, starting as an Air Force air traffic controller after leaving school, serving in Vietnam, then joining the FAA while training as a lawyer at night. After being caught up in the mass firing of air traffic controllers during the 1981 union dispute under President Reagan, he moved repeatedly between law and air traffic control before returning to the FAA in 2001 at the Herndon, Virginia command centre. His first day in the newly assumed national operations manager post began with reports of a hijacking out of Boston, escalating when news came that a flight attendant had been stabbed; by 11.53am, US airspace had been completely cleared of civilian aircraft as a result of his order.