The busiest airport in the world is the Hartsfield-Jackson Atlanta International Airport (ATL), which saw 96,631,755 passengers pass through in transit in the 12 months ending January 2015, nearly 10.6 million more than the world's second busiest airport, Beijing Capital International Airport (PEK). Or as they say in the American south, "whether you go to heaven or hell, you must change planes in Atlanta first."
Earlier this year, Dubai's International Airport (DXB) overtook London's Heathrow Airport (LHR) as the world's busiest international hub as measured by the number of people from other countries who fly through it. And although all airports everywhere are always under construction, the airport that will very likely quickly become the world's biggest airport after it opens is Beijing Daxing International Airport.
But perhaps the most impressive airport ever built is also one of the smallest. Literally. Knuffingen International Airport is the largest miniature model airport in the world, which is located in the Miniatur Wunderland in Hamburg, Germany. At 1:87 scale, it is modeled after Hamburg International Airport (HAM), occupies 150 square meters (1,615 square feet) of space, and was built for just $4.8 million. And yes, it has daily flight operations!
It's a wonderful airport. We just wish the line to check in for our flight was faster....