Monoplane.

The sight and sound of a low flying plane always reminds me of Richard Hannay's adventure in 'The Thirty Nine Steps' when he is pursued by a monoplane as he makes his way on foot across moorland in south west Scotland while trying to avoid both the police and the Balkan KGB.

Low down in the south a monoplane was climbing in the heavens. I was certain as if I had been told that the aeroplane was looking for me, and that it did not belong to the police.....