Airlines' wild 2024: From Boeing troubles to a bankruptcy and a merger

• The drama-filled year in airlines started with a midair door panel blowing off a nearly new Boeing 737 Max 9.
• 2024 also brought an activist campaign to Southwest, an IT meltdown that stranded hundreds of thousands of Delta travelers during the height of summer travel and the first major U.S. airline merger since 2011.
• Holiday demand broke records and airline executives say bookings are strong into 2025.

It's been another eventful year for U.S. air travel. Just five days into the year, a door panel blew off of a nearly new Boeing 737 Max, operated by Alaska Airlines, as it climbed out of Portland, Oregon, after sunset, plunging the airplane manufacturer back in crisis mode and delaying deliveries of new jets for months.

Two weeks later, a federal judge blocked JetBlue Airways' planned purchase of Spirit Airlines, leaving the smaller, battered budget carrier to fend for itself. Struggling Spirit ultimately filed for Chapter 11 bankruptcy protection in November.

The drama-filled year also included an activist campaign at one of the country's most cautious carriers, a tech meltdown that stranded hundreds of thousands of travelers during the height of summer travel and the first major U.S. airline merger since Barack Obama was president.

Federal Aviation Administration chief Mike Whitaker announced he'll step down on Jan. 20, about a year into a five-year term, and the day President-elect Donald Trump is inaugurated, leaving the critical agency that oversees everything from aircraft certification to the U.S. airspace yet again without a leader. Airline CEOs have been clamoring for more air traffic controllers and investment in air traffic technology.

Meanwhile, carriers duked it out for who could be the most "premium" and profitable, with cabins closer to the front of the plane becoming more popular purchases for travelers (sorry to those seeking free upgrades). The top two contenders — stalwart Delta and challenger United — brought most of the industry's profits, and their stock prices hit records, while smaller airlines leaned into roomier seats and announced higher-end credit cards.

Airlines played chicken until the industry trimmed its glut of U.S. flights that were pushing down fares. But the international travel boom, well into the off-season, is showing no signs of slowing down. Through it all, demand for air travel overall smashed records, and CEOs are optimistic about next year, too.

Here's how they each fared in 2024:

Delta Air Lines

The most profitable of U.S. carriers struggled to recover from a July 19 CrowdStrike outage that took hundreds of Microsoft Windows machines offline. It cost Delta Air Lines more than $500 million and left thousands of stranded customers, with a cancellation tally that topped all of 2019. Still, the carrier's stock price hit a record this month.

CEO Ed Bastian told CNBC last week that demand looks strong going into 2025. The airline has been stepping up its premium offerings for high-paying customers, like with three new Delta One lounges, dedicated to travelers flying in that eponymous highest-tier cabin; New York, Los Angeles and Boston opened this year, with more on the way.

It's a sign of Delta's continued focus on upscale travelers and its "premium" brand, which like Spirit for budget travel, has become a punchline about the upper end of travel to the point that a "Saturday Night Live" sketch last week featured Martin Short playing a Delta employee who blocks actor Paul Rudd from entering a coveted Delta Sky Club, saying his name "sounds poor."

Delta stopped short of rolling out a business-class lite product that some analysts expected during a November investor day, but the new lounges could relieve crowding at Delta's popular Sky Clubs.

United Airlines

Can it beat Delta? It's not clear whether the Magnolia Bakery banana pudding is enough to get more travelers to buy up to first class, but United Airlines is making other big moves, like expanding its network to include more premium leisure destinations from Mongolia to Greenland to northern Spain in the next year to capture customers seeking to travel off the beaten path of traditional U.S. airline destinations.

The carrier has thrilled investors with its results this year and set lofty targets for next year. Its stock has more than doubled in 2024, becoming the top-performing carrier.

United is introducing freshly outfitted narrow-body planes with new interiors featuring seat-back screens and Bluetooth connections into its fleet. It announced a Wi-Fi partnership powered by Elon Musk-owned SpaceX's Starlink, and it won't charge for the service, following Delta and JetBlue.

CEO Scott Kirby early in the year said the carrier isn't counting on Boeing's yet-to-be-certified 737 Max 10 and will look at more Airbus planes as an alternative, but he's thrown his support behind the plane maker's new chief executive, Kelly Ortberg.

Southwest Airlines

Say goodbye to open seating. The Dallas-based carrier shocked customers — faithful and frustrated alike — when it said in July that it would start assigning seats and update its uniform cabin to include several rows with extra legroom in a bid to increase its revenue. It was the biggest strategy change for the carrier in its almost half century of flying.

While Southwest said it was working on the changes for months, the carrier announced them after activist hedge fund Elliott Investment Management took a roughly $2 billion stake in the airline and pushed for changes, including CEO Bob Jordan's ouster. He survived the campaign, though ex-CEO and former Chairman Gary Kelly agreed to retire. In a truce, Southwest appointed six new board members in October, including five of Elliott's nominees.

American Airlines

American Airlines ousted its commercial chief, Vasu Raja, in May after a sales strategy that cut out travel agencies in favor of selling directly to business travelers backfired and the carrier abruptly slashed its sales guidance.

Its outlook has improved, and executives are upbeat about year-end demand and into 2025. It signed a new credit card deal with its partner Citi, and will end things with its co-brand partner Barclays, a holdover from American's 2013 merger with US Airways.

Spirit Airlines

The budget carrier comedians love to hate saw its problems snowball this year, starting with a federal judge blocking Spirit's acquisition by JetBlue in January.

Merger off, Spirit was left to face its other problems: a surge in labor and other costs post-pandemic, high competition in domestic markets, a jump in travel demand to places it doesn't fly (like Italy and Japan), and Pratt & Whitney's engine recall that has had an outsize affect on Spirit, grounding dozens of its planes.

Hemorrhaging money with a refinancing deadline approaching, Spirit filed for Chapter 11 bankruptcy protection last month, becoming the first major U.S. carrier to do since American Airlines in 2011. It expects to emerge in the first quarter and it's an open question whether it will again attempt a combination with fellow budget carrier Frontier.

The carrier changed its longstanding business model of charging a low fare and adding on fees for everything else, like seat selection, to offering more bundled options in the summer.

JetBlue Airways

While Spirit saw its stock delisted after filing for bankruptcy, JetBlue forged ahead after the judge blocked the planned acquisition with a singular focus: slash costs and get back to profitability.

New CEO Joanna Geraghty and former commercial chief Marty St. George, who returned to the airline as president in February, set out on JetForward, a strategy that aimed to refocus the airline, which had added too many money-losing routes after the pandemic with its premium-outfitted planes deployed to the wrong places.

The carrier earlier this month announced it would update some of its jets with a domestic business class, to complement its aircraft that feature its top-tier Mint business class.

Its shares are up more than 40% this year through Tuesday's close, topping the S&P 500's performance. Investors have been happy with its latest update that showed better-than-expected revenue.

Alaska Airlines

The airline started the year with the door plug blowout of one of its new Boeing planes, which led to a temporary grounding of Max 9s, and later a payout from Boeing, which makes the Maxes a few miles away in Renton, Washington.

Months later, it was back to focusing on its nearly $2 billion acquisition of struggling carrier Hawaiian Airlines, a combination that got through antitrust regulators in the summer, marking the first merger of major U.S. carriers since Alaska bought Virgin America in 2016.

Alaska has posted solid profits and enjoyed a surge in its stock price of more than 70% so far this year, a nearly threefold premium over the broader market. Executives painted an ambitious picture for investors earlier this month, announcing a global expansion for the combined airline that includes nonstop service on wide-body planes from Seattle — where its top competitor is Delta — to Europe and Asia.

Frontier Airlines

First-class Frontier? The carrier is turning a profit again and is trying to go upscale, planning to outfit its planes with first-class domestic seats.

It's also planning to offer more bundles that include seat assignments, baggage and no change fees.

CEO Barry Biffle said the airline expects to get back to double-digit margins in mid-2025 and credits recent improvement in results with a series of network changes, such as cutting flying during lower-demand days like Tuesdays, Wednesdays and Saturdays and in crowded markets like in Florida and Las Vegas.

Allegiant Air

Allegiant Travel's foray into the hotel business hit a rough patch and said this summer said it would undergo a strategic review for its Sunseeker Resort in Florida. It added this fall that it was closing in on a capital partner for the property that located north of Fort Myers.

The main business, low-cost Allegiant Airlines, has turned a corner, seeing high demand in peak periods, new CEO Greg Anderson told investors this fall. The carrier updated its fourth-quarter guidance that came in ahead of analyst estimates in early December.

Sun Country

With enviable margins, especially for a low-fare airline, the carrier has benefited from its cargo-flying contract with Amazon and competitors cutting capacity from its home hub of Minneapolis, Deutsche Bank airline analyst Mike Linenberg said this month.

"Sun Country's revenue diversity provides the company with an economic moat that has allowed the carrier to maintain profitability during even the most volatile and intensely competitive quarters since the pandemic," he wrote in a Dec. 11 note.

The airline has been successful at switching its schedule with the seasons, ramping up service to warmer destinations in the winter.

Disclosure: NBCUniversal is the parent company of CNBC and NBC, which broadcasts "Saturday Night Live."