The premise of the plot is entirely fictional. The USAAF never experienced the navigational issues depicted in the series. By 1943 the B-17 had achieved a solid reputation as an operational bomber and there is no evidence of a squadron crashing off the coast of Scotland.
When Irene meets David in Venice, the word she uses to describe him that he doesn't understand and which she tells him to look up is "flagitious" which means grossly wicked; guilty of heinous crimes.