The Brief Chicago airports expect over 3.3 million travelers from March 20 to March 31, with O'Hare's busiest day on March 21. Construction on the Kennedy Expressway may cause delays, but it won't stop the high travel volume this spring break season. Chicago airports are expecting a massive increase in travelers this spring break season. What we know:Chicago airports are expected to see more than 3.3 million travelers from Thursday, March 20, to Sunday, March 31. Traveler numbers at Midway and O'Hare are expected to surpass last year's figures, with Friday being the busiest day of the spring break week.