28 FEBRUARY 1970, Page 26

Great Concorde brainwash

Sir: C. 0. I. Ramsden (Letters, 21 February) has obviously taken 'One day's routine super- sonic aircraft operations' to mean one super- sonic flight. But the us source quoted by Peter Smith is thinking of the future, and regards 'routine' as being two and a half flights daily by 200 SSTS. They are also refer- ring to window panes and not windows. Tak- ing their figures of 2,500,000 houses over- flown by one aircraft and sixty window panes per house, the arithmetic checks out at 40,000.

C. D. Crosthwaite St. Stephen's Club, 34 Queen Anne's Gate, London swl