The Stratolaunch aircraft made its maiden flight, reaching 15,000 ft (4,600 m) and 165 kn (305 km/h) in a 2 h 29 min flight. This flight was dedicated to Paul Allen, who inspired the project.

Several Seattle-area landmarks, including the Space Needle, Columbia Center and Lumen Field, as well as various Microsoft offices throughout the United States, were illuminated in blue as a tribute to Allen.