Airline mergers are always sold the same way: a bigger network, lower costs, and more loyal customers. I ranked ten from the last 30 years by how they actually turned out, and the best and worst deals look a lot alike.

The best buyers got something they couldn't have built themselves, kept what customers were paying for, and cut the rest quickly. Delta kept Northwest's biggest hubs and is now worth $50.5 billion, more than United and American combined. Swiss now earns more in a year than Lufthansa paid for it.

The worst buyers paid for a hub or a brand, then shrank it. Alaska bought Virgin America, which Condé Nast Traveler readers voted the best airline in the U.S. 10 years in a row, and retired the name two years later. American bought TWA for its St. Louis hub and cut it in half.

Delta and Northwest filed for bankruptcy on the same day, September 14, 2005, minutes apart. A year later, while Delta was still in court, Doug Parker's US Airways tried to buy it in a hostile bid that grew to about $10 billion. Delta's creditors sided with management, and Parker withdrew in January 2007.

Delta came out of bankruptcy that April and hired Richard Anderson, who used to run Northwest, as CEO. Eight months later, with fuel prices soaring, he agreed to buy his old airline. Northwest had what Delta lacked: big hubs in Detroit and Minneapolis and a Pacific network.

Pilots from both airlines approved one contract before the deal closed, and the two were flying on a single operating certificate 14 months later.

Then Delta decided what to keep. Detroit and Minneapolis, Northwest's biggest hubs, stayed, but Delta stopped growing them. Executives had said no hubs would close, but Delta dropped Memphis in 2013 and moved its Tokyo flights from Narita, Northwest's Asia hub since 1978, to Haneda. The growth went to Seattle, Los Angeles, LaGuardia, and Boston, where the business travelers are. Delta's seats in Seattle went from 2.3 million a year to 7.8 million. I wrote about that in Delta won the last decade. United wants the next one.

It spent on the product at the same time. Delta added Westin bedding in 2013, and by 2014 every business-class seat on its long-haul planes was a flat bed with aisle access. Delta One Suites with doors came later. Delta made $6.2 billion before taxes last year, more than United and American combined.

Willie Walsh started at Aer Lingus as a cadet pilot in 1979, ran it, and became CEO of British Airways in 2005. In 2009, after BA posted a record half-year loss, he agreed to merge with Iberia. The deal nearly fell apart over BA's £3.7 billion pension deficit. IAG started trading in January 2011 at about £6.1 billion, with Walsh as CEO.

Iberia brought Madrid and Latin America, and it was losing €351 million at the operating level in 2012. IAG cut its flying by 15% and dropped Havana, Montevideo, San Juan, and Santo Domingo.

Then it grew Iberia where it was strongest. Iberia now says it's the top airline between Europe and Latin America, with 17% of the market, and last year it had the best margin in the group, 16.2%.

In 2015, Walsh bought the airline where he started. IAG paid about €1.4 billion for Aer Lingus, kept the brand, and used Dublin as a second gateway to North America, with 26 North American destinations this summer. IAG made €5.0 billion in operating profit last year and is worth £17.4 billion.

Swiss was only three years old. It was built out of Crossair after Swissair collapsed in 2001, and it was struggling. Lufthansa paid €45 million for its public shares in 2005, plus an earn-out for the big shareholders capped at €252 million. That's about €297 million at most.

Lufthansa promised to run Swiss as its own premium airline and keep Zurich as a long-haul hub, and it did. It cut up to 1,000 jobs and a lot of flying at Geneva and Basel, but kept the brand and first class. Twenty years later, Swiss's new first-class suites started flying between Zurich and Boston in January.

Swiss made CHF 684 million in operating profit in 2024. Even in a bad year, it made CHF 502 million at a 9.3% margin, almost twice the Lufthansa Group's, and more than Lufthansa paid for the whole airline. Lufthansa is now moving Swiss's network planning, sales, and loyalty to its own headquarters.

Continental walked away from United in April 2008. Two years later its CEO was gone, and his successor, Jeff Smisek, heard United was talking to US Airways. He called United's CEO, Glenn Tilton, and within a month they had a deal. United was the bigger airline, but Smisek ran the combined one, and the planes got Continental's globe.

The 2012 switch to Continental's reservation system went badly. United's on-time rate fell to 64.1% that July, and the CEO publicly asked business travelers to come back. In 2014 it cut Cleveland, a Continental hub, from 199 daily flights to 72.

The network was good enough to recover, and Oscar Muñoz and then Scott Kirby fixed the product: Polaris business class in 2016, then seatback screens and bigger bins on its narrowbodies, and now Starlink Wi-Fi. Since 2009, United's seats are up 73% in Denver and 60% in San Francisco. In Houston, Continental's home, they're up 2%, as I wrote last week. Its market value has quadrupled since 2010.

America West almost didn't survive 9/11. In January 2002 it became the first airline to get a federal loan guarantee after the attacks, and only after being turned down once.

Three years later, its CEO, Doug Parker, then 43, bought US Airways, which had about twice as many employees and was in its second bankruptcy. His team took seven of the eight top jobs, and the deal closed on September 27, 2005, the day US Airways came out of bankruptcy.

The combined airline kept the US Airways name, made Charlotte its biggest hub, and ran on America West's low costs. Parker says its margin went from negative 6% to positive 4% over seven years, while the industry went from negative 4% to 2%, and a 2016 study found the stock mostly beat the S&P 500.

The two pilot groups fought over how to combine their seniority lists, and both rejected a joint contract. Parker kept looking for a bigger partner. He lost Delta in 2007, and in 2013 he got American, which was in its own bankruptcy. His team took over.

In the four big U.S. mergers, the buyer's largest hubs mostly grew, and the bought airline's mostly shrank.

TWA was about to file its third bankruptcy when American agreed to buy it in January 2001 for about $742 million. TWA's shareholders got nothing. American mostly wanted St. Louis. Then came September 11, and TWA's last flight landed there on December 1, 2001.

Once O'Hare's slot limits were lifted in 2002, American could connect the same passengers in Chicago. In 2003 it cut St. Louis from 417 daily flights to 207.

Most former TWA pilots went to the bottom of American's seniority list, and nearly 4,200 former TWA flight attendants were set to be furloughed.

The America West team grew the right hubs at American. Dallas-Fort Worth is up 35% since 2012, and Charlotte, which is cheap to run, is up 25%. But I think it got the product wrong. American put 172 seats on its 737s, up from 160, with less legroom, lavatories 7 inches smaller, and no seatback screens. It shrank at JFK and LAX, where premium travelers fly, and its New York partnership with JetBlue was ruled anticompetitive. In 2024 it reversed a plan to push corporate customers to book directly, and CEO Robert Isom said American had moved faster than it should have. Its new 777s with 70 Flagship Suites are a start.

Meanwhile it spent $11 billion buying back its own stock. American was worth $37.4 billion at the end of 2014. It's worth $8.0 billion now.

KLM spent years looking for a partner. Its alliance with Alitalia ended in 2000, and merger talks with British Airways collapsed months later. In 2003 it agreed to join Air France, and the two kept separate brands and hubs, a lot like IAG would later. Air France's product is good, including new La Première suites to New York. But the group never cut costs the way IAG did at Iberia.

Both groups brought in about €33 billion last year. IAG's operating margin was 15.1%. Air France-KLM's was 6.1%, and KLM's was 3.2%. KLM's finance chief said costs are rising faster than revenue, and the Dutch government is capping Schiphol at 478,000 flights a year. The group is worth €2.6 billion, less than the two airlines were worth in 2003, even after €10.4 billion of government support in 2020.

Alaska won Virgin America in a bidding war with JetBlue in 2016, paying $57 a share, a 47% premium, or about $2.6 billion. It said it wanted to be the West Coast's premier airline, with San Francisco and Los Angeles as hubs. Virgin had customers who loved the purple mood lighting and seatback screens.

Alaska shrank both hubs. Its seats are down 22% in San Francisco and 25% in Los Angeles since 2015, while Seattle, Portland, and San Diego grew. The Virgin name was gone by 2018. Alaska kept the mood lighting, took out the screens, and later sold the Airbus A321neos to American. Its adjusted pretax margin fell from 24% in 2016 to 12% in 2019, and its market value fell 24% while the S&P 500 rose 44%.

Kingfisher launched in 2005 with new A320s and a video screen at every seat. Air Deccan was India's first big low-cost airline, and its founder had called the two businesses "from different planets." He sold anyway. In 2007 Vijay Mallya's company paid Rs 550 crore, about $135 million, for 26% of Deccan, mostly for its track record: India required five years of domestic flying before an airline could fly abroad.

Then Mallya turned Deccan into Kingfisher Red and, in 2011, dropped the low-cost model. Kingfisher never made a profit. It stopped flying in 2012, and Mallya left India in 2016 owing banks about Rs 9,000 crore.

The best buyers didn't treat the airline they bought as the lesser one. Delta hired Northwest's former CEO to run the combined airline. United put Continental's CEO in charge, painted Continental's globe on its planes, and moved everyone onto Continental's reservation system. IAG kept Iberia's name and built its Latin America flying around it. Lufthansa kept Swiss's brand, Zurich, and first class, and Swiss now earns almost twice the group's margin.

The worst buyers treated what they bought as worse than what they had. American put most TWA pilots at the bottom of its seniority list, then cut St. Louis in half. Alaska took out Virgin America's screens and retired the name customers loved. Kingfisher turned India's first big low-cost airline into another Kingfisher and dropped the low fares.

Alaska is getting a second chance with Hawaiian, and it looks like it has learned. It bought Hawaiian in 2024, kept the Hawaiian name on flights to the islands, and is using Hawaiian's 787s to fly from Seattle to Tokyo, Seoul, and Rome, something Alaska couldn't have built on its own. This time it's taking the best of what it bought.