Breathe it in. Can you smell it? That "new airplane smell"? Not all airlines have it. In fact, despite the airplane buying boom of the past few years, some airlines still run fleets so old, you can practically taste the mildew.
Other airlines operate fleets so new that the paint may not even be dry yet on the exterior, nor have the downsized seats had time to pop any springs. What follows is a quick rundown of the top 10 major U.S. airlines -- who has the shiniest new jets, and who's still limping along on ancient airframes.
We begin at the bottom, with ...
Allegiant Air -- average fleet age: 19.8 years
According to Airfleets.net, Allegiant Air (NASDAQ:ALGT) operates the oldest airplane fleet of any major U.S. airline. Allegiant's fleet is so old that its most numerous airplanes are McDonnell Douglas MD-80s and -90s, which ceased production 17 years ago. Allegiant also operates a pair of Boeing 757s (out of production since 2004) and about five somewhat younger dozen Airbus A319 and A320 aircraft.
Delta Air Lines -- average fleet age: 17.0 years
Allegiant's fleet even makes Delta's (NYSE:DAL) look young by comparison -- which is a neat trick, given that Delta actually flies four times as many ancient MD-80s and -90s as Allegiant does. Delta's 747s are even older, averaging 25.9 years across a magnificent seven of these old birds. Delta's youngest jets include 19 Airbus A321s, bought, on average, less than a year ago. Your best bet at boarding a newish plane, though, is by booking aboard one of Delta's 160 nine-year-old Boeing 737 Next Gens.
United Airlines -- average fleet age: 14.3 years
United Continental Holdings' (NASDAQ:UAL) United Airlines was the first of the big "legacy" airlines to begin deployment of Boeing's novel 787 Dreamliner. It now flies 32 of these widebodies -- the newest airplanes in its fleet, at an average age of just 2.5 years. The airline's next youngest plane model is the Boeing 737 Next Gen -- 10.4 years old on average. United flies 340 737s -- by far its most numerous plane model.
Southwest Airlines -- average fleet age: 11.8 years
Unlike the airlines discussed so far, Southwest Airlines (NYSE:LUV) flies exclusively Boeing airplanes. In fact, Southwest flies just one model of Boeing airplane -- the 737. These planes come in either "classic" vintage (737-300s, -400s, and -500s, aged 22 years on average) or "next generation" models (737-600s, -700s, -800s, and -900s). Flying just one type of plane built by one single manufacturer helps to keep Southwest's pilot and mechanic training costs low and cuts down on maintenance costs.
This is one reason Southwest Airlines boasts one of the best gross profit margins in the air business -- 37.4%, according to data from S&P Global Market Intelligence -- despite operating a fleet that's really only middle of the pack, in terms of age.
American Airlines -- average fleet age: 10.8 years
Perhaps surprisingly for a "legacy" carrier, American Airlines Group's (NASDAQ:AAL) average airplane age is a full year younger than Southwest's. Helping American bring its average plane age down have been the airline's post-bankruptcy purchases of new Boeing 787 airliners (25 of them) and Airbus A321s (which now number 208 -- among the most numerous planes in American's fleet).
A more dubious honor that American "boasts" is that it ties Delta for operating the most varied fleet of aircraft -- 11 models in all. This gives American great flexibility in matching the "right" size airplane to the right route, but it probably doesn't do American's maintenance costs any favors.
Hawaiian Airlines -- average fleet age: 10.8 years
With only 51 planes in its fleet, Hawaiian Airlines (NASDAQ:HA) is the smallest of the "major" U.S. airlines on this list. Its fleet splits almost evenly between older Boeing 717s and 767s (15 years-plus), and newer Airbus A330s (aged 4.2 years on average).
JetBlue Airways -- average fleet age: 9.2 years
Founded by a former Southwest exec, JetBlue (NASDAQ:JBLU) famously imitated Southwest's low-cost airline business model -- but not 100%. Whereas Southwest flies an all-Boeing fleet, and all of one model, JetBlue is primarily an Airbus A320 shop. It also flies a fleet of 41 newer Airbus A321s (aged 1.8 years), and five dozen smaller Embraer 190 and 195 aircraft as well.
Alaska Airlines -- average fleet age: 8.9 years
Alaska Airlines (NYSE:ALK) -- like Southwest an all-Boeing 737 shop -- is a really interesting story. In terms of age, Alaska's 8.9-year-old fleet is among the newest in the industry, and it's getting even younger as time goes by.
Last year, Alaska bid $4 billion to acquire rival Virgin America. And Virgin America's fleet, consisting entirely of Airbus A320-family aircraft, is even younger than Alaska's -- 7.4 years. Once it's fully absorbed into Alaska Air in 2019, the average age of Alaska's fleet will drop even further. If calculated today, the two fleets' ages would average out to 8.5 years per plane.
Frontier Airlines -- average fleet age: 7.3 years
Alaska Airlines still wouldn't be as youthful as Frontier Airlines, however. Like Virgin America, Frontier flies an all-Airbus fleet. Like Virgin America, it's a young one at just 7.3 years per plane on average. Unlike every other airline on this list, Frontier is not a publicly traded company, but privately held.
Spirit Airlines -- average fleet age: 6.6 years
Last and least (in terms of age) comes Spirit Airlines (NYSE:SAVE). Like Frontier's, all Spirit Airlines airplanes are Airbuses -- A319s, A320s, and A321s. And as of today, Spirit Airlines holds the honor of operating the youngest airplanes in the country.
But before you go buying tickets on Spirit (or Frontier) based solely on the newness of their planes, here's a fun fact for you: As of the most recent Airline Quality Rating report, Spirit Airlines no longer ranks dead last for quality of service in America. That "honor" has fallen to Frontier Airlines, owner of the industry's second newest fleet -- which just goes to show you that newer isn't always better.