Virgin hot air balloon wafting gently NE from the late lamented Hatfield and approaching the late lamented (*but still revivable?) Panshangar.
Funny thing, I can probably pinpoint just about every SE airfield that's operated in the last 50 years, but Panshangar always eludes me. I did manage to find it once for a visit in the 1980s, vague recollection is of a decrepit T2 hangar with some ex-Danish Whirlwinds decaying within! An acquaintance tells me he went there several times a few years ago with a view to acquiring and rebuilding a bent Saratoga - the arrival of a small daughter diverted his attention!
*the airfield is still extant I see but the buildings have gone. Street view is 10 years old and shows the hangar looking even more decrepit! I can see a wingless Saratoga inside, presumably the one David was interested in.