<P> In October 2015, United appointed Brett J. Hart as its acting CEO, four days after CEO Oscar Munoz suffered a heart attack . </P> <P> United currently operates seven hubs . </P> <Ul> <Li> Chicago--O'Hare--O'Hare is United's largest hub and its hub for the Midwest . United flies approximately 36 million passengers through O'Hare every year, which is about 99,000 people per day, making it also the busiest airline at the airport . United's corporate headquarters are also in Chicago . </Li> <Li> Houston--Intercontinental--located in Houston, is United's second - largest hub . It is the airline's hub for the Southern United States and primary gateway to Latin America . About 33.5 million passengers fly through IAH on United every year, or about 91,000 people per day . United currently has about 78% of the seat share at Bush, making it the airport's largest tenant . </Li> <Li> Newark--The third - largest hub for United in terms of number of flights and destinations and United's primary hub for the East Coast and a gateway to Europe, Latin America and Asia . About 28.5 million passengers fly on United through Newark every year, or about 78,000 people per day . United controls about 81% of the slots at Newark and carries about 68% of all passengers at the airport . United controls all of Terminal C and uses part of Terminal A for United Express Flights . </Li> <Li> Denver--The fourth - largest hub in terms of number of destinations and flights and United's primary hub for the central and western United States . In 2017 United flew approximately 25.9 million passengers through DIA or about 71,000 people per day . As of December 2017, United has about 42% of the market share at DIA making it the airport's largest airline . United occupies all 70 gates of Concourse B at the airport and a recently started 39-gate expansion to all three of the airport's concourses will give United another 11 gates when the project is completed in 2021 . </Li> <Li> San Francisco--The fifth - largest hub in terms of number of flights, and sixth - biggest in terms of number of destinations, and United's primary hub for the West Coast and gateway to Asia and Australia . About 22 million passengers pass through SFO every year on United, which is about 60,000 people per day . United has about 46% of the market share at San Francisco International, making it the biggest airline at the airport . </Li> <Li> Washington--Dulles--The sixth - largest hub in terms of number of flights, and fifth - biggest in terms of number of destinations, and United's secondary hub for the East Coast and gateway to Europe . United has about 65% of the market share at Washington Dulles, making it the largest airline at the airport . About 14 million passengers fly through Dulles every year on United, which is about 38,465 people per day . </Li> <Li> Los Angeles--The seventh - largest hub for United in terms of number of destinations and flights and United's secondary hub for the West Coast and gateway to Asia and Australia . About 10 million passengers fly through LAX on United every year, or about 28,000 people per day . United has 15% of the market share at LAX, making it the third - biggest carrier at the airport . </Li> </Ul> <Li> Chicago--O'Hare--O'Hare is United's largest hub and its hub for the Midwest . United flies approximately 36 million passengers through O'Hare every year, which is about 99,000 people per day, making it also the busiest airline at the airport . United's corporate headquarters are also in Chicago . </Li>

What are the major hubs for united airlines