International aviation is a fast-growing source of greenhouse gases, but current policies don't control these emissions. The International Civil Aviation Organisation is considering market-based options like levies and emissions trading to reduce emissions. The aviation industry prefers voluntary efficiency improvements, but this may not be effective. Implementing emissions charges could reduce air travel demand and increase fuel efficiency. These policies need to be global to prevent industry relocation. Emissions trading and caps are potential solutions for reducing aviation emissions. A technical solution is seen as the best environmental and economic option.