E,
Some of my dad's letters he wrote in England in '44 and '45 (Eighth Air Force, 34th Bomb Group) show strikeouts. In particular, aircraft losses and targets were blacked out. After a few letters, he stopped mentioning those kinds of things.
His letters became limited to "Hello I am fine. The weather is rotten/cold/rainy/foggy. How are you?" That's about all he could write about, as he sure wasn't going to mention the frozen blood that coated the interior of the aircraft after a waist gunner took a direct hit from a 20mm cannon shell or anything like that.
As far as I know, letters going to the servicemen (women) were not censored. No point in it, as the people back home didn't know anything. News was limited to radio and newspapers and was heavily censored too.
--Stan