- The $4 is the world's largest aircraft.
- Its 385-foot wingspan is longer than a football field.
- The aircraft recently completed a runway test in anticipation of its debut flight, which is planned for 2019.
The world's largest plane is so big, it needs two fuselages with separate cockpits.
It's called the $4, and it's designed to launch rockets into space in what is known as $4, which means the spacecraft is between 99 and 1,200 miles above the Earth's surface. (Most space flights, as well as satellites and the International Space Station, are in low-Earth orbit.)
Since it was unveiled in June 2017, the Stratolaunch has undergone a series of tests before it makes its first flight in 2019. On Monday, the Stratolaunch YouTube page posted a $4 of runway tests that saw the aircraft reach a top speed of 46 mph.
Here's a look at the Stratolaunch, and why businesses might want to use it.