The RAF lost 1,023 fighters during the Battle of Britain. Fighter Command would continue to take heavy losses in 1941, as the battle moved to the skies over France.
But Fighter Command's losses were dwarfed by the sacrifice made by Bomber Command in the later stages of the war.
Bomber Command losses:
55,573 killed out of a total of 125,000 aircrew (a 44.4% death rate)
8,403 wounded in action
9,838 taken prisoners of war
A Bomber Command crew member had a worse chance of survival than an infantry officer in World War I.