I used to work up there at the time the wokka went down and one of our guys had a farmhouse next to the Machrihanish perimeter. He swore that something was going on in there in the 80's and early 90s and that he had often heard an unidentifiable engined plane taking off in the early hours when foggy, but that the noise (which was unlike a normal turbine) was lost in seconds as though it had accelerated out to sea at great speed.
Others up there reported strange activity with navy seals seen on the road off the base , however as the yanks were in and out of there, anything was possible (it even had a bowling alley)
I dont doubt that F117s also went in and out of there pre-public unveiling and were responsible for many UFO reports in the North of scotland
If you wanted a base away form prying eyes with no land to fly across to get to remote parts of North America, the Mull has it.
There were even rumours in the town at the time from local coast guard of American personel on scene at the Wokka before any other services arrived there and they all b!!! off staright away. The base was then mothballed in the next few months with the yanks pulling out.
however it could all be overactive imagination in a very remote but scenic place
who knows