For decades, low-cost carriers have come to thrive within the commercial aviation industry by operating business models that eliminate as many expenses as possible, for these airlines to offer fares at enough of a discount to encourage passengers to fly with them instead of competing with legacy airlines.

Most are familiar with the tactics that these low-cost airlines use to cut costs, notably offering very little in terms of inflight amenities and only providing their staff with minimal hospitality training.

One slightly lesser-known tactic used by these airlines is operating flights in and out of lower-demand secondary facilities, airports that are likely to have significantly lower landing and takeoff fees.

Furthermore, when budget airlines are looking to expand their presence and operations, investing in upgrades to these smaller airports is significantly less expensive than higher-demand facilities, where they may have to outbid legacy carriers with deeper pockets for the right to build more gate space.

As a result, budget airlines have become huge fans of operating out of secondary, lower-demand facilities, something which can be observed across the United States.

European low-cost airlines pioneered this operational model, with carriers like Ryanair and easyJet serving destinations across Europe from smaller, lower-demand destinations like London Gatwick (LGW) and Paris Beauvais (BVA).

In the United States, older low-cost carriers like Spirit Airlines and JetBlue are a little more likely to serve higher-demand facilities, but newer-generation budget airlines like Avelo Airlines and Breeze Airways have long been fans of operating from these smaller airports.

Let’s take a deeper look at five secondary airports used extensively by budget airlines to serve larger metropolitan areas.

1 T. F. Green International Airport (PVD) in Providence, Rhode Island

The facility is used extensively by low-cost carriers for its access to the Boston market

Major carriers serving the facility include:

• Breeze Airways
• Southwest Airlines

While Boston Logan International Airport (BOS) is widely known as the largest and most important facility in the Boston region, T. F. Green Airport in Providence is an extremely unique facility that also serves the area.

While initially built and operating for decades as a primary airport for Providence, this facility is now finding a new role as a secondary facility serving Boston.

Southwest Airlines has historically had a strong presence in the area, using Providence as a hub to connect underserved markets south of Boston with major leisure destinations.

Over the past few years, Breeze Airways has steadily built up its presence at the airport, and today T. F. Green is Breeze’s largest operational base, according to a breakdown from Forbes.

2 Orlando Sanford International Airport (SFB)

Allegiant uses this airport as a way to serve Orlando without paying higher fees at Orlando International Airport (MCO)

Allegiant Air, an ultra-low-cost carrier, operates nonstop services from destinations around the country to Orlando Sanford Airport, a secondary facility serving the popular vacation destination.

The carrier serves more than 50 cities from the airport, making it one of the most important in the airline’s network.

3 Chicago Midway Airport (MDW)

Multiple carriers use this facility as a cheaper alternative to the more expensive Chicago O’Hare Airport (ORD)

Major airlines serving the facility include:

• Frontier Airlines
• Southwest Airlines

As the third-largest city in the United States, Chicago has a massive air market, something that would be extremely appealing to low-cost airlines looking to connect vacation-goers with popular leisure destinations. However, budget carriers looking to serve Chicago do face a unique challenge.

Chicago O’Hare Airport (ORD), one of the nation’s largest and busiest airports, is a hub for two major competing legacy airlines, United and American, driving prices at the airport sky-high.

To avoid expensive operating costs, Southwest, Frontier, and multiple other low-cost carriers have turned to Chicago’s second airport as a better alternative for operating flights to and from the city.

4 Houston Hobby Airport (HOU)

The airline offers low-cost carriers a good alternative to Houston’s George Bush Intercontinental Airport (IAH)

While other low-cost carriers like Frontier Airlines and Allegiant do operate some services to and from Houston’s second most important airport, if you are flying to or from Houston Hobby it is more than likely that you are doing so because you are flying Southwest Airlines.

According to the Department of Transportation, Southwest Airlines has more than a 90% market share at Houston Hobby, which serves as one of the airline’s most important operating bases.

5 New York Stewart International Airport (SWF)

This facility offers lower costs than other New York Area facilities

Allegiant Air and Breeze Airways, two carriers that have continued to appear on this list, are the primary operators of nonstop flights from New York’s Stewart International Airport.

The airport is approximately sixty miles north of New York City, and, as a result, the facility is far less convenient than the region’s other major airports.

Nonetheless, it can be convenient to those living in suburban areas north of the city, which are likely the primary demographic that these two carriers are targeting.

The airport has had a few noteworthy moments, however, such as when a Singapore Airlines Airbus A380 diverted to the facility amid a snowstorm in the region.