Chicago O’Hare offers more flight connectivity than any airport in the US, according to the Megahubs U.S. Index prepared by airline analytics company OAG. O’Hare took the top spot by offering as many as 81,913 possible one-stop domestic flight connections during a three-hour window. It’s the third consecutive year that O’Hare has held the top US position in the index. The airport is buoyed by Chicago’s central US location and the hub operations of United Airlines and American Airlines. Both carriers have pursued a strategy of beefing up regional connectivity from O’Hare over the past year. Rounding out OAG’s top five for domestic US connectivity are Delta hub Atlanta, American hub Charlotte, American hub Dallas/Fort Worth, and Denver, which is a United hub and one of Southwest’s largest focus cities.