The Luftwaffe

"...bombers drone in the sky, though she looks for the planes but can't see them." (pg. 1)

Virginia Woolf killed herself in 1941, right after the onset of World War II. The bombers she is referring to are the Luftwaffe. During WWII, London and other Allied cities were bombed heavily by the Luftwaffe under Hitler's orders.

Link: http://www.spartacus.schoolnet.co.uk/GERluftwaffe.htm