Description
Jets leave white trails, or contrails, in their wakes for the same reason you can sometimes see your breath. The hot, humid exhaust from jet engines mixes with the atmosphere, which at high altitude is of much lower vapor pressure and temperature than the exhaust gas. The flag of Scotland consists of a white saltire defacing a blue field. The Saltire, rather than the Royal Standard of Scotland, is the correct flag for all private individuals and corporate bodies to fly.