Normally, when flying between London and New York, the trip takes seven hours. Thus, with the five-hour difference in time between the two cities, you arrive two hours “later” than when you left London. If you could have flown on the now decommissioned Concorde, which traveled at Mach 2 (1,300 miles [2,092 kilometers] per hour—two times the speed of sound), the trip between London and New York would have taken only three hours. Thus, with the five-hour difference in time zones, you would have arrived two hours “earlier” than when you left!