What about the Alien express ? the shuttle from Las Vegas to Groom lake .
Pretty sure a lot of the alien looking attendees at the Star Trek convention in Las Vegas flew in from Area 51 onboard the white 737 with the red stripe . Although one of my friends who used to commute on it just laughed when I asked if I could get a tour of the UFOs . He said even his accreditation and clearance did not let him tour the space ships .