Truth or Consequences, New Mexico - Virgin Galactic successfully carried out its first space flight in nearly two years on Thursday, the company said, after an "enhancement period" to make safety upgrades to its fleet.

It was the fifth time the space tourism company brushed the boundary of space and has been billed as the final test before commercial operations can begin in late June, with members of the Italian Air Force as the first paying customers.

"Touchdown, VSS Unity!" the company tweeted, referring to the name of the company's spaceplane. "Our crew and spaceship are back on Earth after landing smoothly at Spaceport America, New Mexico."

The Unity 25 mission flew four of the company employees to an altitude of just over 50 miles above sea level.

Virgin Galactic's space program has suffered years of delays and a 2014 accident in which a pilot died.

Unlike other companies that use vertical-launch rockets, Virgin Galactic uses a carrier aircraft with two pilots that takes off from a runway, gains high altitude, and drops a rocket-powered plane that soars into space before gliding back to Earth.

The total journey time is 90 minutes, with passengers experiencing a few minutes of weightlessness in the space plane's cabin.

Its first fully crewed flight in 2021 included the company's flamboyant founder, British billionaire Richard Branson.

But what had appeared to be a breakthrough moment for the company was marred by an official safety probe after the spaceplane was found to have dropped below its assigned airspace on its descent.

The Federal Aviation Agency later cleared the company to resume activity after it promised corrective actions.

Virgin Galactic has sold 800 tickets for future commercial flights -- 600 between 2005 and 2014 for $200,000 to $250,000, and 200 since then for $450,000 each.

It competes in the "suborbital" space tourism sector with billionaire Jeff Bezos' company, Blue Origin, which has already sent 32 people into space.

But since an accident in September 2022 during an unmanned flight, Blue Origin's rocket has been grounded. The company promised in March to resume spaceflight soon.