CHICAGO (WLS) -- Chicago's O'Hare Airport is now the busiest airport in the U.S.Last year, O'Hare had more than 900,000 arrivals and departures. That knocks Atlanta's Hartsfield Jackson Airport to the number two spot.Being the nation's busiest airport means there's a lot of people flying in and out of Chicago. A record 105 million passengers flew through O'Hare and Midway last year."Chicago is proud to be the home of the best connected airport in the U.S., and now the busiest airport for total flights, as well," said Mayor Emanuel. "The record number of passengers in 2018 is a testament to the investments we are making to build Chicago's aviation future. With more people visiting Chicago every year, our modernization programs at O'Hare and Midway will keep passengers connected to our two leading gateway airports, and will fuel new opportunities for the City and the region for years to come."City officials attribute part of the increase in air traffic to the addition of nearly 50 new routes, including several international destinations.