Lambert-St. Louis International Airport is old and cramped, but rich in history, and is currently undergoing a major renovation. The airport's sad appearance reflects the disappearance of TWA, which once operated its principal hub here. A little over a decade ago, the airport served more than 30 million passengers annually. In 2009, the number was 12.8 million. Because its surcharges are spread over fewer flights, the airport has less ability to raise capital. Southwest is now the leading carrier at STL. Still, the airport said that the ongoing $70 million improvement project is "the largest interior renovation in its history." Airport spokesman Jeff Lea said Lambert "is one of the most significant airports as far as architectural history in the country, a forerunner of modern terminal airports like JFK and Charles deGaulle." The designer was Minoru Yamasaki, who later designed the World Trade Center. Lea added: "Your survey isn't very scientific: You offered limited choices (after) pre-choosing which airports were the worst." The other airports chose not to respond to requests for comments. We should also mention that one reader of our most beautiful airports story commented: "Another nice one is St. Louis, with the Spirit of St. Louis replica hanging from the ceiling." Lambert Field received 16.5% of the votes.