The original idea to have us all dressed the same was supposedly to stop ivan/slobodan/achmed from identifying the aircrew from the pongos.
The fact is the aircrew would stand out without the need for different clothes. Their captors would only need to ask a question requiring an answer involving more than three sylables or discount anyone with the following traits:-receeding forehead, dragging knuckles and drool from a permanently half opened mouth. Once all the pongoes had been identified all that would be left would be the aircrew; Army, RN and RAF!!