Southwest Airlines
’ network has evolved over 50 years as the carrier expands its route map across North America. The airline first launched service in June 1971 with routes between Dallas’ Love Field, Houston Intercontinental Airport, and San Antonio, adding more complexity and connectivity to its nationwide network as it grew.

While the airline should still be classified primarily as a point-to-point carrier, some of its bases have become essential in connecting passengers to their final destinations. Though the schedules at these bases are not “banked” like a traditional hub, airports like Denver, Baltimore, and Chicago Midway have become “rolling hubs” for the airline.

Boeing 737s of Southwest Airlines

Photo: Joe Kunzler | Simple Flying

While both can play an essential role in airline networks, there are major differences between a traditional, banked hub and a rolling hub. Banked hubs maximize passenger connectivity by having many flights arrive, wait on the ground, and depart in a specified time frame.

Meanwhile, at a rolling hub, flights are turned around quickly and not timed as closely as other departures to reduce costs and increase aircraft utilization. Southwest Airlines, known for its high aircraft utilization, employs this approach heavily. However, legacy carriers like American Airlines and Delta Air Lines have combined this approach with the banked hub concept, offering more daily banks. Hence, aircraft are more productive but still scheduled to enhance productivity.

Chicago Midway is one of Southwest Airlines’ busiest cities. According to Southwest, the carrier first entered the market on March 17, 1985, with eight daily departures to one city: St. Louis, Missouri. The city was the 21st destination on Southwest’s route map, quickly becoming a strategically important destination for the airline.

Chicago Midway International Airport

Photo: Midway International Airport

According to the Department of Transportation Statistics, Chicago’s Midway International Airport
is the second-busiest destination in Southwest’s network based on passengers carried. In the year ending October 2024, the airline carried over 10 million passengers through the facility. As of November 2024, Southwest operates up to 250 daily departures to 79 cities and employs more than 6,000 workers. Given the carrier utilizes 37 gates at the airport, it should come as no surprise that it dominates the market, carrying over 90% of Midway’s passengers.

Despite its impressive and robust collection of nonstop flights from Chicago Midway, using data from aviation analytics firm Cirium, it is apparent that some routes are flown far more frequently than others. Southwest’s 15 busiest routes from the Windy City in January 2025 are a mix of services to key bases, business markets, and leisure destinations. It is important to note the information below only studies outbound frequencies from Chicago Midway.

1

New York LaGuardia Airport

201 monthly flights

Southwest’s most frequent service from Chicago Midway is to the largest city in the United States: New York City. Though the Big Apple has three major commercial airports, Southwest only serves one of these: LaGuardia International Airport. However, Southwest did serve Newark Liberty International Airport from 2011 to 2019, but underperformance and the grounding of the 737 MAX caused them to consolidate at LaGuardia.

LaGuardia Skybridge-1

Photo: Port Authority of New York and New Jersey

The average number of miles flown on the route is 725, and Southwest has 23,831,475 total available seat miles to LaGuardia. Southwest is the sole operator on the route, though many airlines operate flights to the New York area from nearby Chicago O’Hare International Airport.

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2

Phoenix Sky Harbor International Airport

198 monthly flights

The next busiest Southwest route from Midway is to a key base for the airline: Phoenix Sky Harbor International Airport. With almost 200 monthly flights, this route is an impressively busy one for the Dallas-based carrier. The average number of miles flown on the route is 1,444 miles, and Southwest offers a total of 45,783,464 available seat miles to the Arizona city.

Two Southwest Airlines Boeing 737 aircraft at Phoenix Sky Harbor International Airport PHX shutterstock_2314329285

Photo: Robin Guess | Shutterstock

Phoenix serves as a critical market and connecting point for Southwest. The carrier competes heavily with American Airlines, which inherited its Arizona hub after merging with US Airways. Meanwhile, US Airways gained it after it acquired America West.

3

Orlando International Airport

193 monthly flights

Orlando International Airport is also among Southwest’s top routes from Midway. The carrier has been doubling down on the Florida airport, where it currently enjoys its position as the market leader. In addition to being a popular vacation destination, Southwest offers flights beyond the United States and into the Caribbean from its Florida base.

Orlando International Airport tower.

Photo: Orlando International Airport

The average number of miles on this route is 989, and in January 2025, 32,074,259 available seat miles were on this route. Orlando is not the only Floridian airport on this list, but it is the busiest Southwest service to the Sunshine State from Midway.

4

Denver International Airport

190 monthly flights

Denver International Airport is Southwest’s busiest city. In recent years, the airline has made extensive investments in the city to win the favor of Denver passengers. The carrier has:

  • Sponsored three of Denver’s major sports teams (Avalanche, Rockies, and Nuggets)
  • Leased 16 brand-new gates
  • Opened a $100 million maintenance hangar on the airport
Southwest Airlines Planes at Sunrise

Photo: Denver International Airport

Given its importance to the network, Southwest’s impressive 26,923,390 available seat miles on the route should come as no surprise. Southwest passengers can travel via Denver to almost one hundred destinations across North America, and the destination is a powerful gateway to the western United States.

5

Ronald Reagan Washington National Airport

179 monthly flights

Southwest runs frequent services to the capital city of the United States of America. The airline primarily serves this destination via Reagan National Airport, close to downtown Washington, DC. However, the carrier also has limited service to Washington Dulles International Airport, located much further from the city center.

RonaldReaganWashingtonNationalAirport

Southwest first initiated service to the destination in July 2012 after acquiring AirTran Airways, which gave it valuable slot pairs. Today, the airline operates up to 45 daily departures to 17 cities. In total, Southwest has 17,133,909 available seat miles to DC from Chicago.

6

Harry Reid International Airport

171 monthly flights

Sin City is a popular leisure destination, and also the second-busiest destination in the Southwest Airlines network. Thus, Southwest boasts impressive frequencies and 43,033,653 available seat miles to Nevada’s largest city.

Southwest Airlines Boeing 737 MAX departing Las Vegas Harry Reid International Airport LAS shutterstock_2127841190

Photo: Bradley Caslin | Shutterstock

Las Vegas was the 15th destination in Southwest’s network and has remained an essential dot on its route map since. Southwest flies up to 276 daily departures to 70 cities from its Nevada base. Given its popularity among tourists and Southwest passengers alike, the high frequency on this service helps Southwest accommodate the large market.

7

Dallas Love Field

160 monthly flights

Southwest has a robust schedule to its hometown from its Chicago base. Dallas Love Field, the smaller and more centrally located Dallas airport, has played an important role in the company’s history after it fought countless legal battles to retain its right to utilize the airport.

Southwest has 20,782,944 available seat miles to Dallas Love Field this month.

Southwest Airlines Boeing 737 NG and 737 MAX at Dallas Love FIeld DAL shutterstock_2428818329

Photo: Markus Mainka | Shutterstock

The carrier has expressed interest in serving Dallas-Fort Worth International Airport in the coming years, though it is unknown if the airline will act on the idea or how that decision would impact this route.

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8

Kansas City International Airport

148 monthly flights

Southwest boasts an impressive 9,076,860 available seat miles to one of Missouri’s largest cities. The carrier dominates in western Missouri and was the first airline to inaugurate service from the airport’s brand-new terminal. The first departure was bound for Chicago-Midway, and left from Concourse B, where Southwest flights still arrive and depart from.

MCI

Photo: Kansas City International Airport

Southwest offers up 80 departures daily from Kansas City to over 40 destinations nationwide. The airline even offers international service to Cancun, Mexico, though passengers can also fly nonstop to the vacation destination from Midway.

9

Nashville International Airport

134 Monthly Flights

Nashville is the latest Southwest destination to become a crew base for the carrier. The destination’s connectivity makes it sensible for Southwest to deploy frequent service to the Music City from Chicago. Southwest has 8,516,990 available seat miles to the Tennessee city.

08082022-BNA features-09

Photo: Nashville International Airport (BNA)

Southwest recently announced plans to close its Atlanta crew base, which means Nashville will continue to play an important role in connecting Southwest passengers to the southeastern United States. The airline has up to 174 daily flights from the city, though as a new base, this number is likely to increase over time.

10

Houston Hobby Airport

129 monthly flights

Houston Hobby is another key base for Southwest, and the airline boasts 19,323,751 available seat miles to the southern Texas city. Unlike Midway, which has a more limited international route portfolio, Hobby Airport is an important international gateway for Southwest.

Houston Hobby Airport Southwest

Photo: Houston Airports

Frequent services to Houston mean Southwest can offer more options to international travelers. Given its limited presence beyond the United States, flights to Houston are important in accommodating international travelers. In addition to Houston, other cities Southwest operates notable international operations from include Orlando, Baltimore, and Denver.

11

Tampa International Airport

129 monthly flights

Millions of tourists use Tampa International Airport every year as a gateway to beaches, warm weather, and sunshine. Considering this and the fact that Southwest is the largest operator at the airport, it makes sense that Southwest has so many flights from Midway to Tampa.

N464WN Southwest Airlines Boeing 737-7H4

Photo: Vincenzo Pace | Simple Flying

Southwest has a total of 21,901,099 available seat miles to Tampa International Airport. The airline started serving the market in 1996, and today has up to 106 daily departures that connect the destination to bases and colder destinations in the north. Additionally, Southwest connects Tampa with select destinations beyond the states:

  • Havana, Cuba
  • San Juan, Puerto Rico

12

Baltimore/Washington International Thurgood Marshall Airport

128 monthly flights

Baltimore Washington International Thurgood Marshall Airport is Southwest’s fourth-busiest city, serving as the carrier’s major gateway to the northeastern United States. This month, the low-cost carrier has 12,630,592 available seat miles to Baltimore from Midway. It is worth noting that this airport serves the Washington, DC area along with the Baltimore region.

Southwest Airlines Boeing 737 in snowy conditions shutterstock_1305194392

Photo: Steve Heap | Shutterstock

As mentioned, Southwest also serves Dulles and Reagan Airports, so its Baltimore service is not the only way to measure the airline’s presence in the market. However, Baltimore is by far Southwest’s biggest operation in the region. It currently offers up to 235 daily departures to 79 cities, though many of its flights from BWI are focused on the Northeast United States.

13

Minneapolis/St. Paul International Airport

127 monthly flights

Southwest frequently flies between Midway International Airport and Minneapolis/St. Paul International Airport, is a significant hub for premium rival Delta Air Lines. Southwest has 7,521,997 available seat miles to the Twin Cities from Chicago, and it competes directly with Delta Air Lines on the route.

Delta Air Lines Planes lined up at Minneapolis–Saint Paul International Airport.

Photo: Minneapolis–Saint Paul International Airport

Southwest is the second-largest airline based on passengers in Minneapolis, though its operations account for only 5% of the airport’s traffic. This is due to Minneapolis’ status as a Delta hub-the Atlanta-based carrier and its regional subsidiaries dominate the market, and offer flights worldwide from MSP.

14

St. Louis Lambert International Airport

127 monthly flights

Southwest’s first route from Midway was to St. Louis, and the route has proven popular to this day. The short 251-mile hop between the Midwestern cities plays an important role in conveniently connecting the area’s major business centers, and Southwest dominates the market with almost 130 monthly flights.

SW at louisville

Photo: Louisville Airport

Southwest has a total of 5,056,395 available seat miles on the route. The carrier is also the market leader in St. Louis, making this a potentially lucrative market for the budget carrier’s operations. Much of the traffic on this route could be local traffic, as Southwest has extensive operations at St. Louis’ airport that may make stops less necessary for passengers.

15

Hartsfield–Jackson Atlanta International Airport

121 monthly flights

Southwest first entered the Atlanta market following its acquisition of AirTran Airways, which operated a hub in Georgia. Another central hub for Delta Air Lines, Southwest has since shrunk from its predecessor’s peak schedule but still offers frequent service to Chicago and other key bases across its network.

Southwest Airlines Boeing 737s in Atlanta shutterstock_1430520773

Photo: Markus Mainka | Shutterstock

Southwest offers 11,775,810 available seat miles to Atlanta this month, though further schedule reductions are imminent that could likely change Southwest’s presence on this route. With the closing of many Atlanta routes and the shifting of flights to Nashville, there may not be as much of a need for so much service from Chicago.

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