August 18 1940 was the day on which more aircraft were lost on both sides than any other day during the B of B (officially July 10 to October 31 1940).
The Luftwaffe command hoped to destroy two of Fighter Command's main airfields; Kenley and Biggin Hill, both of which were sector stations - unknown to the Germans at the time.
Other targets included airfields at Ford, Gosport and Thorney Island, none of which were vital Fighter Command airfields, and a radar station at Poling.

By the end of the day the Luftwaffe had lost 69 aircraft (94 aircrew killed, 40 taken prisoner, 25 returned wounded) and, with savage losses to one Ju 87 Gruppe, finally decided the Stuka was too vulnerable over Britain. A low altitude attack by 9 Do 17s on Kenley resulted in 8 of the 9 being destroyed or written off after landing. . An additional 25 aircraft returned with repairable damage.

The RAF lost 68 aircraft (10 pilots killed, 1 died of wounds, 19 pilots wounded), 17 of which were training or non operational. 64 other people civilian and military) died during the attacks. (Figures from 'The Hardest Day' by Alfred Price.)
Further information can be found here

Jeff W.

A big to the men who fought in this battle, on both sides.