I am unsure as to the exact definition of 'operational' in this context, but
I understood that although Cody flew from Farnborough in 1908, the earliest
test-flights (and flights) took place at Brooklands airfield near Guildford
(where Cody was also involved). It was also home to the first speed
test-track for motorcars. I think the airfield was further developed for
testing proto-types immediately before and during WWII (certainly the
notorious 'bouncing bomb') - it may be worth checking with the Brooklands
Museum for Motorsport about the exact details relating to flights.
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