Air travel is essential to shuttle fans between games, but most of Brazil's airports are already operating above their nominal capacity.

ECONOMIST: Airports and stadiums are behind schedule

In practice, even that's not guaranteed: if you take 2005 as the last time that the UK was "on trend" (or operating at exactly its capacity), the growth in our nominal GDP between then and 2012 looks about right.

BBC: The Bank of England, the chancellor, and the target