Airlines that once touted globe-spanning destinations, promising adventure, luxury or both, are now leaning on a simpler sales pitch: reliability.

Flight delays and cancellations spiked at several points over the last year, costing U.S. carriers more than $100 million combined and disrupting travel plans of hundreds of thousands of customers. Even some crews have been forced to sleep at airports, a rare last resort for an industry that’s used to accommodating thousands of pilots and flight attendants on the road each day.

As the peak travel season gets underway, the industry risks a repeat of those headaches, and airlines are hoping to get ahead of the problems. Their efforts include massive hiring, better technology for staff and customers, earlier planning for storms, and for some carriers, conservative scheduling or cuts to their spring and summer schedules altogether.

One of airlines’ biggest challenges in what’s shaping up to be a monster travel season is how to handle routine disruptions like bad weather, whether that means delaying flights or canceling outright before passengers arrive at the airport. When planes are packed, airlines have fewer options to move passengers to alternate flights, setting up a game of musical chairs in the sky⁠ — with luggage.

Airlines don’t charge passengers to rebook and big network carriers scrapped standard economy date-change fees to spur bookings during the coronavirus pandemic. But travelers could pay the price if they are forced to buy a new, last-minute ticket on another airline to make it to big events like a wedding or keep other travel plans.

Preventing cancellations is important.

“If we’re reliable, the seat is much more comfortable, the food tastes a lot better, the service that we provide is much more accommodating,” American Airlines CEO Robert Isom told employees in a town hall on April 12. “People really need to feel like they have control of their itineraries.”

American over the last three years has developed its Hub Efficiency Analytics Tool which it debuted last month. Dubbed HEAT, the tool helps the airline to delay more flights ahead of bad weather thunderstorms and avoid canceling them later, according to the town hall. It analyzes data such as crew availability and passenger connections, among other data points.

“The goal is to prevent the cancellations in the first place so that we don’t have to re-accommodate people given the high loads that we expect this summer,” Maya Leibman, American’s chief information officer, said on an earnings call earlier in April.

Carriers including Spirit Airlines and JetBlue Airways have already pared back spring and summer flying. JetBlue, for example, slashed its plan to expand flying as much as 15% this year from 2019 levels and is now planning a schedule no more than 5% up from three years ago as it tries to stabilize its operation while facing staffing shortages, including from pilot attrition.

Schedule cuts for June are deeper at low-cost and ultra low-cost airlines than at network carriers because of staffing shortages and high fuel costs, according to Deutsche Bank analyst Michael Linenberg.

Those carriers “are likely to be disproportionately impacted by this effect given that low fare traffic accounts for a greater share of their revenue base than for the major carriers,” he wrote in a note on April 11.

American plans to fly as much as 94% of its 2019 schedule during the second quarter, while United Airlines expects to fly 87% and Delta Air Lines plans to fly 84% compared with three years ago. Growth potential for major airlines is constrained by a pilot shortage, particularly at smaller regional airlines that feed their hubs.

American said it’s hired 12,000 people since last summer, and plans to add some 20,000 people this year in total. United hired 6,000 people this year, and Delta has hired 15,000 people since the start of 2021, partially to replace the more than 17,000 workers who took the airline up on buyout offers during the depths of the pandemic.

The $54 billion in taxpayer aid airlines received to pay staff during the pandemic prohibited layoffs, but buyouts were allowed.

American, Delta and United all say they are well staffed for the surge in demand.

“We made so much progress with customers during the pandemic and really building the United brand,” United CEO Scott Kirby said on the Chicago carrier’s quarterly call in April. “We’re not willing to sacrifice that customer goodwill for the possibility of short-term profits.”

United has spent years building tools to help passengers rebook themselves and avoid long queues at airports — technology that saves time and labor costs. In 2019, it launched ConnectionSaver, which can help hold an aircraft for connecting passengers, as well as agent-on-demand, a video chat platform for customer service.

Airlines also have to contend with frequent disruptions stemming from bad weather, like those felt at bustling airports in Florida in April.

Thunderstorms have sparked cascades of thousands of cancellations and delays over the past year, disruptions made worse by airlines that scheduled too many flights relative to their staffing levels.

The Federal Aviation Administration is calling airlines for a two-day meeting in Florida early this month to discuss the congested airspace over the state, one of the tourism hotspots during the pandemic, CNBC reported. Flight capacity into some of the state’s busiest airports has already surpassed what was flown in 2019, at the same time space launches and general aviation pick up, the FAA said.

Last week, some executives including at JetBlue and Frontier Airlines put some of the blame on short staffing at a key air traffic control center in Florida.

The Government Accountability Office is examining recent airline disruptions, a spokesman told CNBC.

Thunderstorms are especially tricky for airlines because they’re less predictable than larger systems like hurricanes or winter storms, which allow airlines to cancel flights sometimes days in advance so that crews are in position to restart the operation.

Cutting flights as early as possible “will probably make it smoother for the passenger, but things happen. It is summer,” said Adam Thompson, founder of Lagniappe Aviation consulting firm, and has worked in the industry for more than two decades. “Weather is unpredictable. Every time someone says, ‘This is the worst summer I’ve had,’ I say, ‘Give it a year.'”

Infuriated passengers, used to the conveniences of modern life, where groceries, clothing and ride-shares arrive promptly at one’s door, wait for hours for help from customer service and only grow more frustrated.

“We are used to, ‘Hey, Amazon will bring my package tomorrow. Why can’t you be there on a dime?” said Savanthi Syth, airline analyst at Raymond James. “[Airlines] have to step up and meet those expectations.”

Some extra preparation can help avoid headaches this season.

Here are some tips:

1. Book flights that leave early in the day.

That will give you more of a chance of getting rebooked and avoid the impact of a delay when things go wrong. “Being a lifelong airline guy, I always tell people when they travel, don’t book the last flight of the night. You need something as a cushion,” Thompson said.

2. Check the weather beyond where you are.

Airlines run complex networks, and the weather at your departure point isn’t necessarily the weather at your destination. Many airline apps will show you where your arriving aircraft is coming from. Check that airport’s weather, too.

3. Pick a busier day if you have flexibility.

Thompson said to look at an airline’s schedule for how many flights the carrier is operating to their destination that day. Airlines generally fly less on Saturdays. That could mean less wiggle room if you face disruptions. Thursdays and Fridays traditionally have bigger schedules, but airports are often more crowded, he added.

4. Know what you’re owed.

You are entitled to a refund if the airline cancels or significantly delays your flight, according to the U.S. Department of Transportation. Airlines could offer you a voucher for future travel, but passengers can insist on a refund if they prefer.

Keep in mind that low-cost airlines like Southwest don’t have interline agreements with other carriers that allow them to book travelers on a competitor. While airlines use these agreements sparingly, if a carrier doesn’t have one it could reduce your chances of an alternative flight.

5. Be kind.

Gate agents and reservations agents, many of them new employees, are also under stress. Keeping calm is more effective all around. Simply put, Thompson said, don’t be a jerk.