Contrails – those curious long cloud-like streaks in the sky and tell-tale signs a jet has passed – could be linked with global warming. With some research suggesting a connection, the IATA is currently pushing for more research while stating too little is known about their impact to act on. The EU, for its part, is already acting and implementing new regulations. The aviation industry is responsible for around 2% of the world’s human-made global CO2 emissions, although its impacts extend beyond CO2 emissions. A number of airlines are currently involved in contrail research – including American Airlines.