Is this what you are talking about?
Click Here for Google
Maps
If so... here are some screenshots:
It is an odd 'end' to a road and does appear to disappear in the mountain.
... however, when looking close i don't see too much in the form of a hangar door. I appears to be flat ground that has been worn from vehicles
turning around. That being said, why would vehicles head up that seemingly dead end road?
What does strike me as odd is the poor job google has done on those images. There is plenty of watermarks half scrubbed and poorly stitched and
smudged areas.
Will be interesting what others make of the images.