[DanBC]

RAF Bomber Command had appalling rates of attrition through WWII.

http://en.m.wikipedia.org/wiki/RAF_Bomber_Command

The wiki article gives good explanation of how bombing developed during WWII - starting as a weapon to terrible to be used (based on poor quality data); with general agreements not to kill civilians; realising that bombers were hopelessly inaccurate; changing tactics to allow bombing of civillian populations, including the (to my mind) war crimes of fire bombing.

> Bomber Command crews also suffered an extremely high casualty rate: 55,573 killed out of a total of 125,000 aircrew (a 44.4% death rate), a further 8,403 were wounded in action and 9,838 became prisoners of war.

That's pretty much "toss a coin".