International air travel from the United Kingdom refers to the commercial carriage of passengers between the UK and the rest of the world. In 2008, London Heathrow Airport which is also the busiest international airport on earth handled 67,054,745 passengers which is more than the total population of the United Kingdom. The 20 busiest airports in the UK handled close to 230 million passengers in 2008 (185 million of whom were international passengers). The geographical size of the UK means that many flights that would be considered domestic in for example the United States are actually international (i.e. the distance from Heathrow to Paris-Charles de Gaulle Airport is roughly the same as the distance between John F. Kennedy International Airport and Washington Dulles International Airport). The London airports, Heathrow, Gatwick and Stansted alongside Manchester Airport rank amongst the world's busiest airports by international passenger traffic. According to 2008 statistics the best served nations by direct flights from the UK were France, Italy, Spain, the United States and Germany with 50, 34, 33, 31 and 29 respectively. Overall Spain was the nation that saw the most passengers arrive from the UK in 2008, with a total of 34,557,729 (almost double the number that flew to the United States)
Increasing demand for air travel in the UK has resulted in a conflict between the desire to cater for that demand and the environmental consequences of doing so. In the past 25 years the UK air transport industry has seen sustained growth, and the demand for passenger air travel in particular is forecast to increase more than twofold, to 465 million passengers, by 2030. Two airports; London Heathrow Airport and London Gatwick Airport, are amongst the top ten busiest airports in the world for international passenger traffic. Whilst more than half of all passengers travelling by air in the UK currently travel via the five London area airports, regional airports have experienced the most growth in recent years, due to the success of 'no-frills' airlines over the last decade.
The ability of the existing airport infrastructure to meet forecast demand is limited, and government policy published in 2003 supports the development of additional airport capacity by 2030 to address this. The strategy is generally based on making the best use of existing facilities, although an additional five new runways nationwide are considered to be necessary, three of them at the London airports of Stansted, Heathrow and, towards the end of the timeframe involved, Gatwick. This policy is designed to be a balanced and measured approach to the future of the air transport industry; one that recognises both an economic advantage in providing for growth in demand for air travel and also the need to address the consequent environmental impacts. The strategy has been criticised by the House of Commons Environmental Audit Select Committee, by environmentalist and campaign groups, and in research papers, for implementing a predict and provide model that overstates the economic advantages whilst paying insufficient heed to the environmental consequences.
Support for airport expansion is based on an economic case that regards the air transport industry not only as an important industry in its own right, but also as a facilitator of growth for the economy as a whole. One study predicts that the government's strategy will realise an additional £13 billion per annum in Gross Domestic Product (GDP) by 2030. Another study which is critical of the government approach, and which favours addressing environmental impacts through increased taxation of air transport, indicates a negative economic benefit resulting from airport expansion. In 2006 the industry was responsible for over 6 per cent of all UK carbon emissions, a figure that is set to rise as demand increases. Under current strategies of emissions reduction and growth in air transport, air travel in the UK could account for up to 50 per cent of the UK carbon budget by 2050. Industry attempts to address this issue are longer term efforts based on technological and operational improvements, whilst government policy is based on the inclusion of air transport within emissions trading schemes. Critics advocate a shift in government policy to address environmental impacts by constraining the growth in demand for air travel, primarily through the use of economic instruments to price air travel less attractively. Local environmental issues include noise and air quality, and the impact of these, particularly in the case of the former, is subject to debate. Government policy generally is that these are local issues best addressed locally, and has introduced legislation designed to facilitate this.
