Its wingspan is longer than a football field. The tail is 50 feet from the ground. It was made by reassembling parts from two used Boeing jetliners.

On Saturday, the world’s largest airplane took flight for the first time.

The twin-fuselage plane, called the Stratolaunch, flew for about two and a half hours over the Mojave Desert in Southern California, reaching a speed of 189 miles per hour and an altitude of 17,000 feet in its maiden voyage, the Stratolaunch team said.

“The flight itself was smooth, which is exactly what you want the first flight to be,” Evan Thomas, a test pilot with Scaled Composites who flew the Stratolaunch, said at a news briefing. “And for the most part, the airplane flew as predicted, which is again exactly what we want.”