Hypersonic air travel is anything that travels at Mach 5, or five times the speed of sound. The U.S. was once a leader in developing supersonic and hypersonic technology, but has taken “our foot off the gas,” according to Mark Lewis, executive director of the National Defense Industrial Association’s Emerging Technologies Institute.

Watch the video to find out more about how the U.S. fell behind Russia, China and possibly North Korea, and how we’re spending billions to catch up.

Hypersonic air travel, for both military and commercial use, could be here within the decade.

The $770 billion National Defense Authorization Act signed into law Tuesday calls for investing billions into hypersonic research and development, making them a top priority for Washington. The next step is congressional approval to allocate the money for the technology to the Pentagon.

“If you are traveling at hypersonic speeds, you’re, you’re going more than a mile per second,” said Mark Lewis, executive director of the National Defense Industrial Association’s Emerging Technologies Institute. “That’s important for military applications. It could have commercial applications. It could also open up new, new ways of reaching space.”

Hypersonic is anything traveling above Mach 5, or five times the speed of sound. That’s roughly 3,800 mph. At those speeds, commercial planes could travel from New York to London in under two hours.