The Stratolaunch is dubbed the world’s largest plane sporting a 385-ft wingspan and tipping the scales at more than 500,000 lb. After firing up its six engines in September 2017, it now nears the speed needed for takeoff, reaching 136 mph in its latest string of runway tests.

According to New Atlas, the company hasn’t released exact takeoff speed requirements, however, “it does say it takes off just like any other aircraft, which typically lift off in the 150-180 mph range (240 to 285 km/h).”

In late February 2018, the behemoth traveled down the runway at 46 mph. Then a few months later in October, videos surfaced of the Stratolaunch hitting a maximum of 90 mph in its medium-speed taxi tests. With its recent jump to 136 mph, its maiden flight edges closer.