Pilots carrying comprising material
I was a pilot in the RAF at the time of the conflict.Part of our training and pre-flight procedures for operational sorties was to 'sterilise' ourselves of any useful information before 'walking' for the sortie in case of just this sort of eventuality. A pilot wouldn't carry that sort of information in paper form. Even if he did he wouldn't have the time to look at it in flight so why bother taking it?