The Navy celebrates Earth Day by showcasing a supersonic flight test of the “Green Hornet,” an F/A-18 Super Hornet strike fighter jet powered by a 50/50 biofuel blend. The test, conducted April 22, 2010, at Naval Air Station Patuxent River, Md., drew hundreds of onlookers. (U.S. Navy photo/Released)
The Navy is pursuing what it calls a Hypersonic Air Launched Offensive Anti-Surface (HALO) weapon. But the missile’s top speed might not qualify as hypersonic, a program…