On the morning of 13 April 2019, the widest aircraft ever built rolled down the runway at Mojave in California, lifted two fuselages and six engines off the ground, and flew for two and a half hours. Its wings stretched 385 feet from tip to tip, wider than an American football field is long.

The man who had paid for it was not there to see it. Microsoft co-founder Paul Allen had died six months earlier. His giant, nicknamed Roc after the mythical bird said to be big enough to carry an elephant, nearly became a museum piece. Instead, it became the mothership for one of America's most important hypersonic test programmes.

Paul Allen's Space Dream

Allen founded Stratolaunch in December 2011 with a simple idea: carry a rocket high into the atmosphere under a giant aircraft and launch it from there, avoiding fixed launch pads and bad weather. The aircraft was built by Scaled Composites in Mojave, the company that had already built SpaceShipOne and its carrier aircraft for Allen.

To lift a fully fuelled rocket, the aircraft needed enormous size. Scaled gave it two fuselages joined by a single straight centre wing, with the payload hanging from the middle. The six engines are Pratt & Whitney PW4056s, the type that powers the Boeing 747-400, and only the right-hand fuselage has a cockpit for the crew.

The First Flight

Test pilot Evan Thomas took Roc up from Mojave Air and Space Port on 13 April 2019. The flight lasted about two and a half hours, reached more than 17,000 feet and topped out at around 165 knots as the crew checked handling and systems before landing back at Mojave.

Stratolaunch's chief executive at the time, Jean Floyd, said watching the aircraft fly was emotional, and that he had whispered a thank-you to Allen. By then the company's future was already in question.

Near Death and a New Mission

Without its founder, Stratolaunch ceased operations in May 2019 and dropped its rocket plans. In October 2019 the company was bought by the private equity firm Cerberus Capital Management, which kept the aircraft and gave it a new purpose: hypersonic flight testing.

Hypersonic weapons, which fly at more than five times the speed of sound, had become a top Pentagon priority, but the United States had few ways to test them often and affordably. A reusable hypersonic test vehicle launched from a giant carrier aircraft offered a solution.

Talon-A: Mach 5 and Back

The answer was Talon-A, an uncrewed, rocket-powered hypersonic test vehicle that hangs under Roc's centre wing. The pair flew their first captive-carry test in October 2022, and on 5 March 2024 Roc released the expendable TA-1 for its first powered flight.

The reusable TA-2 followed. Stratolaunch announced in May 2025 that it had flown faster than Mach 5 on two flights, in December 2024 and March 2025, and was recovered after each flight, making it a reusable hypersonic test platform for the Pentagon.

Stratolaunch's own film of the TA-1 first flight in March 2024, released from Roc over the Pacific.

A Mothership With a Future

Demand for hypersonic testing is now high enough that Roc is getting company. On 30 September 2026 Stratolaunch announced it had bought a former Air New Zealand Boeing 777-200ER to convert into an additional Talon-A carrier. Roc remains the original, and still the widest aircraft ever to fly: a machine built to launch rockets that found its real calling launching the future of high-speed flight.

Sources: Wikipedia (Scaled Composites Stratolaunch), Space.com, Stratolaunch, The Aviationist, SpaceNews, AIAA