And how to close off prohibited commercial traffic between Iran and Dubai, a major re-export hub in the Gulf, is another unanswered challenge.

另一个棘手难题是如何取缔伊朗和海湾地区出口中转中心——迪拜之间的地下商贸往来。

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EgyptAir is a major contributor to achieving the goal of converting Cairo international airport into a hub connecting traffic flows and serving global air travel.

在埃及航空公司的极大贡献下，开罗国际机场已成为连接国内、地区与全球航空飞行的枢纽。

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And it's apparently because policing especially in Guinea-Bissau, which is the weakest link, is so poor that these Latin American, South American drug cartels are using this region as a major transit hub to especially traffic cocaine as the drug of choice, and that's on to Europe.

NPR: West African Drug Trade, War of Words in Sudan

The decision to expand should help ensure that Heathrow keeps its status as a major hub for air traffic, which brings tens of thousands of jobs to the area, and has other indirect benefits, such as making the UK a more attractive place to locate regional headquarters for companies that are expanding into Europe.

BBC: Terminal 5: Welcome arrival or major infringement?

Most other major hub cities, such as New York, split traffic between two or more major airports.

BBC: Why is Atlanta the world��s busiest airport?