Texas is the second-most populous state in the US. According to the Census Bureau, more than 29 million people were Lone Star State residents in 2020. It is home to two major metropolitan areas, Houston and Dallas, and two major US airlines are headquartered in the Dallas area.
Southwest Airlines
was founded and based out of Dallas Love Field
(DAL), where it operates to this day. 
American Airlines
is nearly 100 years old and headquartered in Fort Worth, near Dallas. The airline’s largest hub is nearby at Dallas/Fort Worth International Airport
(DFW). Although not headquartered in Texas, 
United Airlines
has a large hub at George Bush Intercontinental Airport (IAH) in Houston.
- United – George Bush Intercontinental Airport (IAH)
- American – Dallas/Fort Worth International Airport (DFW)
- Southwest – Dallas Love Field (DAL)
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In 2023, more than 81 million passengers flew through DFW, which is one of the world’s busiest airports. Data shows this was an 11.5% increase over 2022, which saw just over 73 million passengers. By the end of September, DFW registered more than 65 million passengers, compared to 60 million in 2023, representing an 8.4% increase.
According to data from Cirium, the three airlines operate nearly 4,000 flights from various airports in Texas to the two Chicago airports, Chicago O’Hare International Airport (ORD) and Chicago Midway International Airport (MDW). Among the three, Southwest has the most flights, but United is just behind Southwest, and American is not far behind. The breakdown is below:
- Southwest Airlines – 1,326 flights
- United Airlines – 1,317 flights
- American Airlines – 1,261 flights
Of these nearly 4,000 flights, only 2,376 are from the hubs mentioned above. When analyzing flights from DAL, DFW, and IAH, Southwest actually has the smallest market share and United has the largest. The breakdown is as follows:
- United Airlines – 940 flights
- American Airlines – 871 flights
- Southwest Airlines – 565 flights
Between the three airlines, there are more than 400,000 seats available in December. United alone has more than 167,000.
United Airlines
United is headquartered in Chicago, and its primary hub is O’Hare. As mentioned above, it also has a hub in Houston. Naturally, there are a significant number of flights between the two cities. But there are also a high number of flights from Chicago to Dallas.
More than 650 of United’s 940 flights in this month are between Houston and Chicago. The flight between IAH and ORD is only 925 miles long but is served up to 13 times daily. According to Cirium, on any given day, there are a few thousand seats available on the route.
In total, United has more than 127,000 seats available between ORD and IAH next month. This averages out to 194.9 seats per departure, as the airline deploys several aircraft types on the route. The Airbus A321neo
, which only joined United’s fleet in late 2023, is scheduled to operate up to four daily roundtrips between the two cities.
As mentioned above, several aircraft types are deployed on the IAH-ORD route. The full list is below:
- Airbus A321neo – 200 seats
- Boeing 737-800 – 166 seats
- Boeing 737-900ER – 179 seats
- Boeing 757-200 – 176 seats
- Boeing 777-200 – 364 seats
- Boeing 737 MAX 8 – 166 seats
- Boeing 737 MAX 9 – 179 seats
Photo: Lukas Souza | Simple Flying
Between DFW and ORD, United has 143 roundtrips (286 flights) scheduled in December. Because of a variation in aircraft use, there are more seats available from Dallas to Chicago than in the other direction. Data shows 20,134 seats available from DFW to ORD and 19,911 in the opposite direction. This breaks down to 140.8 seats per departure going to Texas, and 139.2 going to Chicago.
On its peak days, the DFW-ORD route has six roundtrips, but most days have four to five. United also uses several aircraft types on this route, but since it does not connect two hubs, the planes used are smaller. See the list below:
- Airbus A319
- Airbus A320
- Boeing 737-800
- Boeing 737-700
- Boeing 737 MAX 9
American Airlines
American currently holds the title of the largest airline in the world, but United is close on its tail. Its headquarters is located almost right by Dallas/Fort Worth International Airport (DFW), which is the second-largest airport in the world by land mass and the airline’s biggest hub. Like United, ORD is also a hub for American.
Photo: Markus Mainka | Shutterstock
According to Cirium, American has 871 flights scheduled between Dallas/Houston and Chicago. Naturally, the busiest route is from DFW to ORD, with more than 700 flights. In December, there are more than 125,000 seats available on the route.
Operations between ORD and DFW fluctuate between 11 and 12 daily roundtrips, but most days have 12. On its busiest days, there are more than 4,000 seats available on the route. Several aircraft types are deployed by American, but unlike United, which uses a widebody for some of the flights mentioned above, American only uses narrowbodies on the hub-to-hub route.
The full list of aircraft used between ORD and DFW is below:
- Airbus A319 – 128 seats
- Airbus A320 – 150 seats
- Airbus A321 – 190 seats
- Airbus A321neo – 196 seats
- Boeing 737-800 – 172 seats
Photo: Cassiohabib | Shutterstock
There are three to four daily flights from Chicago to Houston on American. This is split between mainline and regional operations, with Envoy Air and Republic Airlines operating flights. For mainline operations, American uses the following planes:
- Airbus A319
- Boeing 737-800
For regional operations, Envoy uses:
- Embraer E170
- Embraer E175
Finally, Republic Airlines uses the Embraer E175.
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Southwest Airlines
Southwest is famous for several reasons. First, it is the world’s largest operator of Boeing 737 aircraft. Southwest’s fleet is so large that it has the fourth-largest commercial fleet in the world.
Photo: Markus Mainka | Shutterstock
The airline was founded more than 50 years ago after its founders drew a triangle on a napkin and dreamed of starting an airline. The triangle connected Dallas, Houston, and San Antonio. Since its founding, the airline has operated on an open-seating policy, which is set to change.
Southwest is also known for its friendly staff and including two free checked bags on every ticket. Headquartered in Dallas, the airline naturally has a significant portion of the market share between Texas and Chicago. According to Cirium, Southwest has more than 500 flights scheduled in December.
Unlike the other airlines on this list, Southwest is the only one to operate flights to Chicago Midway International Airport (MDW). In fact, most of its flights between Dallas and Chicago are to Midway. Data shows there are 389 flights between Love Field and Midway. This breaks down to between four and seven daily roundtrips.
Photo: Midway International Airport
Southwest uses several 737 variants between DAL and MDW. The list is below:
- Boeing 737-800 – 175 seats
- Boeing 737-700 – 143 seats
- Boeing 737 MAX 8 – 175 seats
To ORD, Southwest has between two and three daily roundtrips from DAL. This totals more than 29,000 seats in December. Like the route to MDW, Southwest deploys the same variants.
Bonus airlines and routes
Other airlines operate flights between Texas and Chicago, namely Frontier Airlines and Spirit Airlines. The two carriers are the biggest ultra-low-cost carriers (ULCC) in the US, and Spirit Airlines is currently in bankruptcy. But, in addition to these two airlines, the three listed above have more routes outside of their hubs.
Southwest operates flights on the following routes between Texas and Chicago:
- Austin – Chicago Midway
- Austin – Chicago O’Hare
- El Paso – Chicago Midway
- Houston (Hobby) – Chicago Midway
- San Antonio – Chicago Midway
Even though Southwest only has 565 flights between Dallas and Chicago, it has more than 1,300 between all of its Texas and Chicago routes. Data shows there are more than 217,000 seats available.
Photo: Austin Chamber of Commerce
United, which has 940 flights between Houston and Chicago, has more than 1,300 flights between Texas and Chicago. The airline operates the following routes that were not mentioned above:
- Austin – Chicago O’Hare
- Dallas – Chicago O’Hare
- San Antonio – Chicago O’Hare
- El Paso – Chicago O’Hare
American Airlines has nearly 1,300 flights between Texas and Chicago, but only 871 are from Dallas. The rest are on the following routes:
- Austin – Chicago O’Hare
- Houston – Chicago O’Hare
- San Antonio – Chicago O’Hare
- El Paso – Chicago O’Hare.
Outside of its route from Dallas to Chicago O’Hare, the busiest route is from Austin, with up to three daily roundtrips. Data shows there are more than 22,000 seats available.
Photo: The Global Guy | Shutterstock
Spirit Airlines, which has more flights than Frontier, has two routes from Texas to Chicago:
- Dallas/Fort Worth – Chicago
- Houston (Intercontinental) – Chicago
Frontier Airlines, like Southwest, operates to both Chicago airports. Frontier has the following routes:
- Dallas/Fort Worth – Chicago Midway
- Dallas/Fort Worth – Chicago O’Hare
- Houston – Chicago Midway
- Houston – Chicago O’Hare
Spirit has 194 flights, compared to Frontier’s 170. On seat offering, Spirit only has 459 more seats than Frontier, 34,473 and 34,012, respectively.