Macrihanish was always "rumoured" to have been a bolthole for the "F-19 Stealth Fighter" as it was known back in the mid-80's, although i don't think there was ever a shred of evidence to back this up, although if you ever read the Groom Lake "Aurora sighting" story in one of the big publications of the day (I think it was Aircraft Illustrated?) it seems that any basis of fact wasn't a big factor in the reporting of these things anyway!
The suggestion was that anything like the Stealth fighter would need a decent runway length, hence the selection of Macrihanish, although again I think the entire thing is wishful thinking by the writer