Apart from forced landings,
all normal flying whether at London Airport or Farmer Giles' farm strip is at an 'aerodrome':
From ANO2016
“Aerodrome”—
(a) means any area of land or water designed, equipped, set apart or commonly used for affording facilities for the landing and departure of aircraft; and
(b) includes any area or space, whether on the ground, on the roof of a building or elsewhere, which is designed, equipped or set apart for affording facilities for the landing and departure of aircraft capable of descending or climbing vertically; but
(c) does not include any area the use of which for affording facilities for the landing and departure of aircraft has been abandoned and has not been resumed;