Here we go again...
"I, Clark C. McClelland, former ScO, Space Shuttle Fleet, personally observed an 8 to 9 foot tall ET on his 27 inch video monitors while on duty in the Kennedy Space Center, Launch Control Center (LCC). The ET was standing upright in the Space Shuttle Payload Bay having a discussion with TWO tethered US NASA Astronauts! I also observed on my monitors, the spacecraft of the ET as it was in a stabilized, safe orbit to the rear of the Space Shuttle main engine pods."Here is the source for the quote.
I don't think this guy is playing with a full deck but maybe he's being truthful as far as he knows it. I just don't think something like this can be kept a secret for so many years.