After many years of speculation, Lockheed Martin has finally confirmed that its Skunk Works unit has started building the first SR-72 flight demonstrator. The aircraft is envisioned with an air-breathing hypersonic propulsion system that has the ability to accelerate from standstill to Mach 6.0 using the same engine, making it about twice as fast as the SR-71. At speeds of Mach 5 and above, aerodynamic friction becomes hot enough to melt conventional metallic airframes, so engineers are looking to composites such as high-performance carbon, ceramic, and metal mixes, for fabrication of critical components. The SR-72 follows the US Air Force’s hypersonic road map for developing a hypersonic strike weapon by 2020, and a penetrating ISR aircraft by 2030. Click here for the first image in today’s viral picture gallery. Continue reading for a viral video showing the first four minutes of Spider-Man: Homecoming.