QFE is a silly thing which is used only (as far as I know) in the UK. It is really confusing and should be abolished.
If a pilot can't work out how high he should be if required to be say 1000ft above the airfield elevation then it's amazing he ever got through the PPL exams. If the elevation is say 1200ft then he needs to be there at 2200ft. This is no rocket science, and avoids the mistakes caused by flying with QFE instead of QNH.
The other benefit of flying on QNH is that the altimeter always reads the altitude, which then relates to obstacle heights shown on the charts. So you have, right in front of you, a constant readout which gives you information on obstacle clearance. QFE is completely useless for anything en-route.
It gets much worse if instrument flying. Easy to make a fatal error then, if getting the two mixed up. So instrument pilots usually use QNH only.
Does anyone know why the UK hangs onto QFE?