Frontier Airlines is the US’s seventh-largest operator by passengers. In the 12 months leading to March 2026, the country’s Department of Transportation shows that the airline transported 33.7 million passengers. 93% flew domestically.

The ultra-low-cost carrier carried 4% of the vast country’s domestic traffic. It had a similar proportion of short-haul international traffic to Mexico, Central America, and the Caribbean. In both senses, it will benefit from the now-defunct Spirit Airlines.

Frontier Has Added 38 Routes

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Frontier’s entire route network in July 2025 was compared to what is available in the same peak summer month in 2026. This was done using the carrier’s latest schedule submission to OAG. Examining the two time periods against each other reveals some notable changes.

Compared to last July, Frontier has added 38 routes. 33 are domestic and five are international. They’ll be examined separately in the following sections. However, the budget carrier will not operate 99 routes that were served in the same month in 2025. As such, its overall network has reduced in size. The same is the case for Frontier’s competitor, Allegiant Air. Frontier plans 293 routes, down by 18% year-over-year.

Despite having a smaller network footprint, Frontier’s flights have actually increased, which is primarily due to having more services on existing airport pairs. This process is called densification. An average of 701 daily round-trip services are scheduled in July, up from 569 in the same month last year (+23%). It is going to be the airline’s best month to date for activity.

These 33 Domestic Routes Have Launched Or Will Do So

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The 33 domestic routes Frontier has launched or plans to launch soon are shown in the following interactive map. This map enables readers to zoom in and out to see when each domestic route started (some were resumptions). Most of the links launched in November or December 2025. As such, they did not operate last July but will do so next month. That’s why they are included.

A handful of routes operated until sometime between January and June 2025 but returned later in the year. They did not operate last July. They include Dallas/Fort Worth International Airport (DFW) to San Juan, Detroit to Las Vegas (LAS) and Tampa, Los Angeles International Airport (LAX) to San José (California), Milwaukee to Orlando International Airport (MCO), New York LaGuardia to MCO, and Nashville to MCO.

Ten domestic routes have been inaugurated thus far in 2026 or will take off soon. They are summarized below. Eight have been part of Frontier’s network before, while all except one was served by Spirit until earlier this year. Two airport pairs will launch next month, with Frontier’s entry meaning they each have two airlines again following Spirit’s exit. It’ll face Southwest Airlines in both markets, with Frontier providing lower fares. The trade-off, as usual, will be Frontier’s even simpler product and lower frequencies.

These Five International Routes Have Started

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Compared to last July, these international routes are now served by Frontier: MCO to Guatemala City (five weekly to daily in July 2026 on the A320neo), San José (Costa Rica; three weekly A321ceo/A321neo), and San Pedro Sula (four weekly A320neo), along with DFW to Guatemala City (two weekly A320neo) and San Salvador (two weekly A320neo). They all started in December 2025. Only MCO-San José has been part of Frontier’s map before (2021-2022).

All three routes from MCO were served by Spirit until earlier this year. Following that airline’s cessation, Guatemala City and San Pedro Sula were unserved, hence the appeal to Frontier. Launching so-called ready-made markets is a common way to grow. Frontier will be the fourth airline operating between MCO and San José, alongside JetBlue, Southwest, and Volaris. With 326,000 round-trip local passengers last year, booking data shows that MCO is the largest US market to/from Costa Rica.