Airth is the posh name of the Central Scotland Airport opened in May 1939 and became RAF Grangemouth in September 1939.
Before my time.
But more recently (late 60s/early 70s), and again in a study about 30 years later, Airth was once more identified as a possible location for a Central Scotland Airport, to replace both Edinburgh and Glasgow airports.
Edit: "Scale" model of the original Central Scotland Airport aka RAF Grangemouth at the local Heritage Trust Museum:
