Rollout of world's largest aircraft

[a_majoor]

This is far larger than any other giant transport, and unlike the planes which carried the Space Shuttle, is designed to suspend the load under the centre portion of the wing. This is designed to carry rockets to high altitudes for launch, and is certainly much larger than any comparable aircraft (the most famous air launcher is a modified B-52 used by NASA, and VirginGalactic has a much smaller custom built carrier aircraft).

I suppose a giant streamlined cargo pod could be built to be suspended from the cradle, which would make the aircraft semi practical (you could use it for other purposes than carrying a rocket), but this is mostly for interest:

http://newatlas.com/stratolaunch-worlds-largest-plane/49820/?li_source=LI&li_medium=default-widget

Stratolaunch, the world's largest plane, emerges from its hangar for the first time
Rich Haridy  May 31, 2017
The world's largest plane is out of its hangar for the first time

After four years of construction, the world's largest plane has just rolled out of its giant hangar for the first time. The Stratolaunch aircraft, which boasts a wingspan greater than a football field, is designed to carry rockets into the stratosphere, where they are released before firing their engines and continuing on into space.

This massive hangar was custom-built to construct the giant plane The first sight of the Stratolaunch
The giant twin-fuselage aircraft, which weighs in at 500,000 lb (226,000 kg), is designed to carry payloads up to 550,000 lb (249,476 kg). With a wingspan of 385 ft (117 m), it outreaches the 320-ft (97.5-m) wingspan of the Spruce Goose. The craft is powered by six Boeing 747 engines and was constructed in an enormous, custom-designed, 103,257 sq-ft (9,593 sq m) hangar in the Mojave desert.

Towed from the hangar on its 28-wheel landing gear, this is the first time the aircraft has been publicly displayed, with the team now preparing for fueling tests, engine runs and ultimately a first flight planned for 2019.

Stratolaunch Systems was launched seven years ago by Microsoft co-founder Paul G. Allen, and is one of several companies racing to develop an air-launch-to-orbit aircraft. Currently, to get an object into orbit it needs to take off from a launchpad, which is costly and time-consuming.

Earlier this year, Virgin Galactic spun off a dedicated company called Virgin Orbit that is aiming to achieve a similar goal. Its plan is to use a 747-400 to carry rockets up to an altitude of 35,000 ft (10,670 m) before releasing them.

Stratolaunch, on the other hand, has been working on designing this unique aircraft to do the same job. It already has its first customer lined up, partnering with Orbital ATK in late 2016 in a plan to use the massive aircraft to launch Orbital's Pegasus rockets into orbit.

The company is aiming for a first launch demonstration some time in 2019.