A mock air battle between an F-16 jet and the military’s new and oft-troubled F-35 stealth jet showed that the F-35 is too sluggish to hit an enemy plane or dodge gunfire, according to a report. The F-35 has cost the US military more than a trillion dollars since work on it began, making it the most expensive weapon in history. The mock air battle, staged in January over the Pacific Ocean, was to... 

Arcing through the hazy air above California, this is the incredible sight of a scramjet as it flies at six times the speed of sound. The experimental aircraft set a record for hypersonic flight, blazing through the air for more than three minutes at Mach 6, or more than 4,500 mph. The X-51A Waverider scramjet was released from a B-52 bomber last week before its engine took it to Mach 6 and it flew...