Classicly

Nearly everyone believed that the purpose of Project Star was to construct "flying saucers" (the inadequate name had stuck through the years) for use in reaching out to the other planets. Only the men who were working there, and a few others in government and in the military forces, knew that the disks were not intended for extra-terrestrial flight—there were rocket projects galore for that—but for journeys in the atmosphere or slightly above it, at speeds incredible even in 1970. The name Project Star had not been chosen to mislead anyone, but it had done so and nobody bothered to correct the impression. Secrecy had become an ingrained national habit in the past thirty-odd years.