Aerospace startup Hermeus is moving its headquarters to El Segundo from Atlanta as it aims to build autonomous hypersonic aircraft for the military, the latest sign of revival in the region's aerospace and defense sectors. The company, valued at $1 billion, is opening executive offices and a facility where it will design and build its next prototype, a supersonic plane intended to hit Mach 3 " faster than any modern warplane. The company's goal is to eventually develop a hypersonic plane reaching Mach 5, or five times the speed of sound, and Southern California has the engineering talent base to help achieve that, executives said.