Which US Routes Are Served By The Most Airlines?

There are large numbers of domestic US routes with three airlines offering non-stop service, based on analyzing every route offered in May using the latest scheduled information from OAG. If airport-pairs with four competing carriers are considered, that number falls to about 100. Pretty significant, with a strong emphasis on core leisure markets (especially Las Vegas and in Florida), airports serving major metropolises, and Atlanta. But what about domestic routes with five, six, and seven airlines?

Domestic US routes with five airlines

Some 23 routes have five airlines in May, as shown in the map below. Denver has five, more than any other airport, with Cincinnati, Los Angeles, Miami, Minneapolis, and Seattle all having a quintet of carriers, as summarized below in order of total flights. Denver benefits from being a United hub, a vital airport for Southwest and Frontier, an increasingly fertile ground for ULCCs, a major city in its own right, and a gateway to outdoor activities.

  1. Denver-Cincinnati: United, Delta, Frontier, Southwest, Allegiant; up to six daily departures in May
  2. Denver-Los Angeles: United, Southwest, Delta, American, Spirit; up to 22
  3. Denver-Miami: American, Southwest, Frontier, Spirit, United; up to eight
  4. Denver-Minneapolis: Delta; United; southwest; frontier; Sun Country; up to 16
  5. Denver Seattle: United; southwest; Alaska; Delta; frontier; up to 21

Until recently, Denver-Los Angeles had six operators, but that reduced to ‘just’ five following the exit of Frontier, which operated it for many years until mid-2021. The ULCC no longer serves LAX at all, preferring instead to focus on other LA Basin airports: Burbank, Ontario, and Orange County. They’re cheaper, less congested, and have lower head-to-head competition, although Orange County is, of course, heavy slot-constrained.

Domestic US routes with 5 airlines in May 2022

All of these routes have five airlines in May. As you’d expect, most fares are relatively low, also because of the nature of the markets. For example, in Q3 2021, Austin-Las Vegas had an average fare of just $156 according to DOT data. With fewer direct competitors, San Antonio-Las Vegas achieved a 23% higher fare. Image: GCMap

Those with six carriers

Just three routes have six airlines, all involving Los Angeles. In May, Hawaiian will utilize the A330-200 between Los Angeles and Kahului, replacing the A321neo that is currently deployed. Nevertheless, the A321neo will remain the leading aircraft on the airport-pair thanks to American’s sole use of it. The equipment is also the most-used to Kona too.

  1. Los Angeles-Kahului: American, United, Delta, Southwest, Alaska, Hawaiian; up to 12 daily departures in May
  2. Los Angeles-Kona: United, American, Hawaiian, Southwest, Delta, Alaska; up to eight
  3. Los Angeles-Reno: American, Delta, United, Alaska, Southwest, JetBlue; up to 15

The author’s favorite is Los Angeles to Reno. In 2019, it had three operators (American, United, Southwest), which doubled to six in 2020, partly thanks to JetBlue exiting Long Beach to concentrate on Los Angeles. This huge increase in competition necessarily resulted in the average fare falling significantly in Q3 2021 versus 2019 (down by 31% to $114), according to DOT data. While you’d expect that to meaningfully grow passenger volume, traffic fell by 12%, mainly due to Los Angeles, and California generally, being so badly hit by coronavirus.


Regional jets will have eight in ten flights between Los Angeles and Reno in May. While the Embraer 175 is the number-one type, United will primarily use 50-seat CRJ-200s, as shown here. Photo: Vincenzo Pace | Simple Flying.

Domestic US routes with seven operators

No domestic US airport-pair has more than seven airlines competing head-to-head in May, with four routes having the maximum. They’re shown below, again all involving Los Angeles. All but Las Vegas have seen airlines added since the pandemic struck. Sin City said goodbye to Allegiant, Frontier, and Sun Country.

  1. Los Angeles-Austin: American, Delta, Southwest, Alaska, United, JetBlue, Spirit; up to 16 daily departures in May
  2. Los Angeles-Honolulu: United, American, Hawaiian, Delta, Southwest, Alaska, Sun Country; up to 18 daily
  3. Los Angeles-Las Vegas: Southwest, Delta, American, United, Alaska, Spirit, JetBlue; up to 33
  4. Los Angeles-Salt Lake City: Delta, American, Alaska, United, Southwest, JetBlue, Spirit; up to 22 daily

It is Salt Lake City that stands out for the author. Spirit will begin serving the Utah airport in May with three routes, including the 590-mile (949km) link to Los Angeles. The once-daily service will begin on May 26th. And when it does, the airport pair will have seven carriers.

Which of the routes mentioned above have you flown? Let us know in the comments.

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