The world's largest airplane may be grounded after just one flight.

Stratolaunch Systems Corp., which built a huge rocket-toting aircraft named Roc to launch satellites (and eventually people) into space, will soon shut down, Reuters reported on Friday (May 31), citing four anonymous sources. However, Stratolaunch officials have told Space.com the company "remains operational" as of now.

Microsoft co-founder and longtime space enthusiast Paul Allen established Stratolaunch in 2011. But the billionaire died last October at the age of 65, and his sister Jody — chair of Stratolaunch parent venture Vulcan Inc. and trustee of the Paul G. Allen Trust — decided to "set an exit strategy" late last year, according to Reuters.

"Jody Allen decided to let the carrier aircraft fly to honor her brother’s wishes and also to prove the vehicle and concept worked, one of the four people said," Reuters wrote.

That flight took place April 13 from California's Mojave Air and Space Port. During the 2.5-hour test jaunt, Roc reached a peak altitude of 17,000 feet (5,180 meters) and a top speed of 189 mph (304 km/h), Stratolaunch Systems representatives said at the time.

RELATED: Stratolaunch Test Photos: The World's Largest Plane in Action

Roc's wingspan is a record-breaking 385 feet (117 m) — longer than an entire football field, including the two end zones. The aircraft is designed to haul a launch vehicle up to about 35,000 feet (10,700 m), at which point the booster will separate and make its own way to space.

Another company, Richard Branson's Virgin Orbit, plans to air-launch satellites in a similar manner, though with a much smaller carrier plane. And Virgin Orbit's sister outfit, Virgin Galactic, employs a carrier plane to get its six-passenger SpaceShipTwo suborbital spaceliner aloft.

Stratolaunch Systems' impending demise is not official, however; a spokesperson told Reuters that the Seattle-based company is still kicking. And Space.com got the same message when we reached out to the company.

"Stratolaunch remains operational," a company spokesperson told Space.com via email on Friday. "We will provide an update when there is news to share."

Mike Wall's book about the search for alien life, "Out There" (Grand Central Publishing, 2018; illustrated by Karl Tate), is out now. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook.

SIGN UP FOR THE MACH NEWSLETTER AND FOLLOW NBC NEWS MACH ON TWITTER, FACEBOOK, AND INSTAGRAM.