The high-level political intervention also has an important impact on the sales of aircraft. Different buyer’s decisions of spending such a huge amount of money always rely partly on the political reasons since the support and interference of government could affect the future of buyers. For example: currently China is the biggest market for Boeing and it is expected to remain so for the next 20 years. In fact, China, through its considerable purchases of Boeing planes, has managed to gain a lot of political leverage in the U.S