"Scrambled egg" was wartime services slang for the extra gold braid on your uniform when you were promoted in rank, so yes, the prospect of getting some "scrambled egg" might have 'egged' some pilots on. But (a) the phrase wasn't particular to Spitfire squadrons, and (b) if an answer contains EGG then you wouldn't expect the clue to contain it too. I think this is a case where if some of the other clues are as sloppy as that, then you can suppose this one is too; but if the others are meticulously correct, you have to think again.