Contrails are artificial clouds that form behind aircraft flying at high altitude. Jet fuel (also known as AVTUR for AViation TURbine fuel) is made up of long-chain hydrocarbons, from nonane (C9H20) to hexadecane (C16H34). When these long-chain hydrocarbons are burnt they combine with oxygen to form carbon dioxide and water. The water vapour in the … Continue reading What are contrails?