Contrails ( /ˈkɒntreɪlz/; short for "condensation trails") or vapour trails are long thin artificial clouds that sometimes form behind aircraft. Their formation is most often triggered by the water vapour in the exhaust of aircraft engines, but can also be triggered by the changes in air pressure in wingtip vortices or in the air over the entire wing surface. Like all clouds, contrails are made of water, in the form of a suspension of billions of liquid droplets or ice crystals.

Depending on the temperature and humidity at the altitude the contrail forms, they may be visible for only a few seconds or minutes, or may persist for hours and spread to be several miles wide. Persistent contrails are thought to have a significant effect on global climate.

The main products of hydrocarbon fuel combustion are carbon dioxide and water vapour. At high altitudes this water vapour emerges into a cold environment, and the local increase in water vapour can raise the relative humidity of the air past saturation point. The vapour then condenses into tiny water droplets which freeze if the temperature is low enough. These millions of tiny water droplets and/or ice crystals form the contrails. The time taken for the vapour to cool enough to condense accounts for the contrail forming some way behind the aircraft's engines. At high altitudes, supercooled water vapour requires a trigger to encourage deposition or condensation. The exhaust particles in the aircraft's exhaust act as this trigger, causing the trapped vapour to rapidly condense. Exhaust contrails usually occur above 8,000 m (26,000 ft), and only if the temperature there is below −40 °C (−40 °F).

Namie Amuro (安室 奈美恵, Amuro Namie^?, born September 20, 1977) is a Japanese R&B and pop singer, entertainer, and former actress who at the height of her popularity was referred to as the "Teen Queen" and the title "Queen of Japanese Pop Music". Born in Naha, Okinawa, Amuro debuted at the age of 14 as an idol in the girl group Super Monkey's. Though mostly unsuccessful, the group gained popularity during their final year together with the single "Try Me (Watashi o Shinjite)" (1995). Amuro left Toshiba-EMI after releasing two more solo singles; she continued her music career as a solo singer with the then-small independent label Avex Trax. Under the guidance of producer Tetsuya Komuro, Amuro quickly became a commercial success, producing several million-selling records and starting several fashion trends. Her single "Can You Celebrate?" (1997) became Japan's best selling single by a solo female artist. However, in late 1997, Amuro put her career on hold to focus on her pregnancy and marriage.