What if, just five years after the Sept. 11, 2001, attacks, seven flights departing London’s Heathrow Airport for five American cities and two Canadian cities mysteriously exploded over the Atlantic Ocean? What if this terrorist attack took place in the space of just three hours? What if the United Kingdom had detected no explosives either in the carry-on or checked luggage of the passengers?

Unlike on 9/11, no heroes such as Flight 93’s Todd Beamer or FDNY Battalion Chief Orio Palmer could have mitigated this loss of life. The bombers would have hidden in the bathroom out of sight. And then it would be too late. And while British authorities would likely have banned carry-on liquids as a precaution following the attacks, it would have likely taken them at least a week to figure out that the attackers had smuggled liquid explosives inside bottles made to look like soda drinks, and that they had used both real batteries to power detonators hidden inside hollowed out batteries. Considering these major flight routes, 1,500 to 2,000 people would have been killed in those three hours.