The airplane experience has changed a lot since the 1960s, when tickets could cost up to five times more than today's prices, passengers could smoke on the plane and have as much booze as they could drink. Now, we have budget fares, tiny seats, and baggage fees. But one aspect of air travel hasn’t changed much over the last few decades: how fast the plane goes. We’re still flying at the same speeds we did back before man had made it to the moon.

Despite upgrades in aviation technology, airplanes fly around the same speeds as they did 50 years ago, according to the explainers Wendover Productions (who have previously covered how budget airlines keep prices low). Flights are scheduled to take longer, though, thanks to the congestion of planes getting in and out of airports, meaning that we actually spend more time flying the same routes. Like most terrible things about flying, the lack of speed has to do with the airlines' bottom lines.

One reason is that the speeds we were flying in the ‘60s are still the most efficient for the engines we use. Commercial aircraft are typically powered by turbofan engines, which are most efficient at speeds of 400 to 620 miles per hour. Military aircraft can go much faster with turbojet enginesmore than 1500 miles per hour in some cases—but that takes an incredible amount of fuel.

The Concorde aircraft could reach speeds of 1300 miles per hour at cruise altitude, but it used 46.85 pounds of fuel for every mile flown and could seat only 100 passengers. Boeing’s new 787 Dreamliner, which has a cruise speed of 648 miles per hour, uses only 18.7 pounds of fuel per mile and can seat 291 passengers. The speed just wasn’t worth it for airlines, and the Concorde was retired in 2003.

Dive into the world of airplane engines in the video below: