Does anyone know why UA (and previously CO) blocks out seats 21D, E and F on the 757-200 flights between EWR and LHR? I was told they are for the pilots when I asked at LHR one time, but I have never seen anyone sit in them when I have been on these flights. I thought it might be due to the length of the flight, but neither shorter nor longer flights between EWR and European cities have them blocked out.

As an elite flyer it would nice if we could use these empty seats rather than be crowded it three across in 21A, B and C.