On September 1, 1974 Major James V. Sullivan, 37 (pilot) and Noel F. Widdifield, 33 (reconnaissance systems officer), flashed across the starting line (radar gates in New York) at approximately 80,000 feet and speed in excess of 2,000 miles per hour. Exactly 1 hour 54 minutes and 56.4 seconds later, they had set a new world speed record from New York to London England. The average speed was 1,807 statute mph over the 3,461 statute mile course, slowing to refuel one time from a specially modified KC-135 refueling tanker. The aircraft was placed on static display at Farnborough Air Show for 1 week. It marked the first time the secret plane had been on public display outside of the United States. Clarence L. "Kelly" Johnson, the aircrafts designer, was on hand for the event. He remarked, "It (the SR-71) has exceeded all my expectations."

Another historic speed record was set on the return trip to the United States. Capt Harold B. Adams, 31 (pilot), and Major William Machorek, 32 (reconnaissance systems operator), set a speed record from London to Los Angeles. They returned the Blackbird 5,447 statute miles in 3 hours 47 minutes and 39 seconds for an average speed of 1,435 miles per hour. The difference in the two speed records was due to refueling requirements and having to slow over major US cities. Even so a large number of people in Los Angeles reported broken windows due to the sonic boom.