Footpath closure due to airfield construction.

Contemporary Ordnance Survey maps no longer appear to not map sites of national defence and many a layout for second world war airfields or rather the visible traces are now included in the mapping

A quite common occurence is when a footpath is marked up to the boundary of an airfield only to stop and is continued at another point on an opposite boundary. Does any one know the mechanism by which the footpaths were closed (temporary or just the duration of the war)?

I am also curious as to how disused airfields were disposed of, did the previous owners have any rights as to re'aquisition or were they just sold by tender or auction in an upscaled version of "Army Surplus Clothing".
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The return of land that was requisitioned is covered by the Crichel Down Rules

Land was offered back to the land owners