Inside the world's largest plane, which has a wingspan longer than a football field and will debut in 2019

Stratolaunch Systems is owned by Paul Allen, who cofounded Microsoft.

Allen's goal for the company and its namesake aircraft is to "provide convenient, reliable, and routine access to low-Earth orbit."

It would do so by launching rockets toward space from mid-air, which the company hopes will be less expensive than current, commercial space launch options.

That would be particularly useful for companies who want to send satellites into space.

Its 385-foot wingspan makes it wider than a football field, and the larges airplane by wingspan.

The aircraft is 238 feet long, 50 feet tall, and has six high-bypass-ratio turbofan engines.

It weighs 500,000 pounds and needs 28 wheels between its two fuselages.

The aircraft needs to perform a series of tests before it can take flight.

The company most recently performed a runway test where the aircraft reached a maximum speed of 46 mph.

The Stratolaunch's first flight is scheduled for 2019.