Complex sentence: Thus if a pilot happened to be seen by a fellow aviator or worse, a WAAF, while climbing into a Lysander they tended to get a look of slight regard, as they clearly did not appear to be on the sharp end of the war effort.
Split into simpler sentences: Thus if a pilot was seen by a fellow aviator climbing into a Lysander they tended to get a look of slight regard. Clearly they did not appear to be on the sharp end of the war effort.