A Lockheed Martin boss has refused to explain a video splashed on social media showing a UFO saucer-like aircraft being wheeled into a top-secret US military base.

"I can't [speak about it]," said a grinning Jeff Babione, Lockheed Martin's Skunk Works Vice President and General Manager when asked about the seemingly extraterrestrial tech.

"Grinning." ;-) To read more, click here.