Lockheed Martin Corp. said Tuesday it was on the verge of a technological breakthrough that would allow its conceptual SR-72 hypersonic plane to reach six times the speed of sound, or Mach 6, according to reports. Marillyn Hewson, CEO of Lockheed, said that a hypersonic demonstrator aircraft the size of an F-22 stealth fighter could be built for less than $1 billion.

The company is working on an “aerodynamic configuration” that would allow the successor to the famed SR-71 Blackbird spy plane to fly at Mach 6 speed, Hewson said, according to Reuters. Such a plane would give the U.S. military a major advantage, allowing it to reach targets before the enemy could react.

Orlando Carvalho, head of Lockheed's aeronautics division, said the U.S. government's current plan was to manufacture and deploy a hypersonic weapon, before moving on to develop and deploy a hypersonic aircraft, Reuters reported. He added that the U.S. could make a hypersonic weapon by the 2020s, but a hypersonic aircraft like the SR-72 would be manufactured in the 2030s.

Carvalho also said that Lockheed has been working on an engine for the hypersonic aircraft with Aerojet Rocketdyne, a rocket manufacturer, Financial Times reported. He added that innovation was “much more rapid” now than in the past because of Aerojet’s engine work and Lockheed’s work on aircraft materials, the report added.

“That said, it’s going to require a significant amount of development work, investment and maturing of the technology,” Carvalho, according to the Financial Times.

Lockheed announced plans for the SR-72 hypersonic plane in 2013, billing it as an aircraft that would fly twice as fast as the SR-71 Blackbird.