Some of us have either read, heard or even experienced how much travel has changed throughout the decades. But what we no longer see or do inside an airplane is not the only aspect of travel that’s dramatically changed over the years.

Flying is the other part that’s been altered—we are now spending more time in the air than we did 60 years ago. Yes, you guess that right. We have actually slowed down rather than speed up. Why? Because flying slower saves more money for the airline.

Back in the 1960s, airplanes flew at a speed of 604 miles per hour. Nowadays, they are flying anywhere between 552 to 587 miles per hour. As many can suspect, flying at quicker speeds requires additional fuel. And with jet engines continuously advancing—and becoming larger—the fuel power these monsters require to travel at faster speeds, compared those used decades ago, can get expensive. This is especially true for larger aircrafts such as the A380 or Boeing 787 (Dreamliner).

On the other hand, smaller planes are built differently in terms of weight, allowing them to save even more fuel while flying slower. For instance, one analysis showed how an airline saved up to $13 million USD in a single year by just adding an additional two minutes to their flight time. Another analysis revealed how another airline was able to save more than 162 gallons of fuel on flights from the US to Europe by adding on a mere eight minutes.

Nowadays, pilots can map out the best and most fuel-efficient flight with special planners. However, this will most likely mean they will add on another few minutes in order to save several gallons of fuel (or thousands of dollars)—be it a long-haul trip from Australia to Europe, or a domestic flight within the US.