score:4
By 1939 around 100 permanent airfields had been constructed.
Year Military Licensed Civil
1935 60 90
1940 280 0
1945 720
1950 270 90
1955 210 105
1960 130 115
According to the Aeroplane Directory, in 1945 the UK contained 720 operational service airfields (including flying-boat bases), occupying in total around 360,000 acres; by 1965 the number had dwindled to around 100 with a further 50 or so being reserved for other military purposes.
–– Nine Thousand Miles of Concrete: A Review of Second World War Temporary Airfields in England (PDF)
Apparently also of interest;
–– USAAF AIRFIELDS Guide and Map (PDF)