'There is something seductive about aircraft vapour trails, those long streaks – ice, carbon dioxide, soot and metal – that slice the sky. I’ve often wondered what the first person who noticed one thought it was, or what they’d look like to someone who didn’t know airplanes existed. Perhaps magical: linear clouds being drawn straight onto the blue; a symmetrical interruption to the random shapes of clouds. Or perhaps they’d be so unheimlich as to be cause for alarm.' (Ashley Hay: Introduction : Seeing through the digital haze : New perspectives for a new age)