Also, by searching "Stonehenge airfield" in Google images, I came across this link to old plans of the airfield and its buildings:-

http://www.airfieldinformationexchange.org/community/showthread.php?8214-Stonehenge

As for the track, it might be the old route of Byway 12, which has, according to the link below, been moved further west over the years:-

http://www.sarsen.org/2013/10/using-crisp-packet-to-date-stonehenge.html