"What was the most exciting thing you saw?" I ask.

"I found a list of officers' names," he claims, "under the heading 'Non-Terrestrial Officers'."

"Non-Terrestrial Officers?" I say.

"Yeah, I looked it up," says Gary, "and it's nowhere. It doesn't mean little green men. What I think it means is not earth-based. I found a list of 'fleet-to-fleet transfers', and a list of ship names. I looked them up. They weren't US navy ships. What I saw made me believe they have some kind of spaceship, off-planet."

"The Americans have a secret spaceship?" I ask.

"That's what this trickle of evidence has led me to believe."

"Some kind of other Mir that nobody knows about?"

"I guess so," says Gary.

"What were the ship names?"

"I can't remember," says Gary. "I was smoking a lot of dope at the time. Not good for the intellect."

http://www.guardian.co.uk/weekend/story/0,,1523143,00.html

That's what I like solid evidence from someone smoking dope.
Of course it helps a bit if understand that terrestrial refers to land and sailors have calling non-sailors "land lubers" for centuries.
That they call sailors who don't spend anytime at sea terrestrial wouldn't be very surprising.
And sailors, especially high ranking officers which is has lots of experience at sea as non-terrestrial oppose to desk jockey is within the realm of the possible.

"terrestrial
adj 1: of or relating to or inhabiting the land as opposed to the
sea or air [syn: tellurian, telluric, terrene] "
http://dict.die.net/terrestrial/