As the range and passenger load of aircraft grow, so does the importance of international hub airports such as London's Heathrow.

ECONOMIST: The music of the metropolis

In May, the company announced that it was planning unspecified new routes, and recently the passenger load reached the "upper 60% range, " says Lebron.

FORBES: No Rest For A Weary Start-Up

Concorde was an engineer's delight: it took the jet-bomber technologies that had evolved at the end of the second world war and pushed them to the frontiers of the possible, or indeed beyond the frontiers, given that the aircraft's initial prototype could not have crossed the Atlantic with a full passenger load.

ECONOMIST: Why Concorde was never the right way to speed up air travel