Its an old one but....
During the tense days at the height of the Battle of Britain, some desk navigator at the War Office decided that it was imperative to boost the morale of the pilots. It was decided that the best way to do this was for the pilots to meet some of the young ladies among the British Aristocracy in a social setting. To ensure that some of the young hellions among the pilots didn't get carried away, a Wing Commander would be present to protect the finer sensibilities of the debutantes from any excesses of enthusiasm.
The first such event duly came about, and among the participants selected was Paddy, a young Irish pilot. A bit shy at first, he quickly thawed with a few belts of Irish whisky and an admiring circle of young ladies, and before long he was regaling them with the details of his latest sortie against the Luftwaffe. The Wing Commander casually strolled over and pricked up his ears just as Paddy said, "And there I was, with barely enough fuel to make it back to the airfield, when I suddenly spotted these three Fokkers diving down at me out of the sun..."
The Wing Commander swooped in at once. This was exactly the sort of thing that could be misunderstood by the pampered and protected young debutantes, and the last thing he wanted was a complaint to Air Vice-Marshal Dowding about foul-mouthed pilots. "Excuse me a moment please, Paddy." he interrupted, and turned the audience. "Let me explain, ladies that the Fokker is among the Luftwaffe's finest aircraft, and both their fighters and bombers have given us a great deal of trouble in combat. Thank you Paddy, you can carry on with your story now."
Paddy shook his head soberly. "Yes Wing Commander, sure and you can say the Fokker is a very fine fighting machine, and no one will deny it. However, these three Fokkers I'm talking about were all Messerschmidts..."