In the wake of this week’s unprecedented wave of U.S. flight cancellations, experts and passengers alike are weighing in on how flyers can better prepare for a disrupted itinerary.

While multiple explanations have been put forward to explain the chaos that stranded thousands of passengers in the last few days — the majority of which was led by Southwest Airlines and included weather, staffing, and technology issues — there should be one key takeaway, experts say: Flyers can no longer rely on their airline when something goes awry, and instead should have the savvy and, where possible, the financial resources — to take matters into their own hands.

“The days are gone when you could just take off without a backup plan,” said Kathleen Bangs, a former commercial airline pilot and spokeswoman for FlightAware, a company that provides flight-tracking services.

First, all travelers should download their airline’s digital app, or get familiar with sites like Google Flights, in the event they must look for an alternative flight, she said. Some airlines, including Southwest, no longer have automatic agreements in place that allow for rebooking on another airline free of charge, she said.

And because of consolidation within the industry, there are fewer planes flying overall, leaving many passengers with generally fewer options, said Scott Mayerowitz, the executive editor of The Points Guy travel site. All the more important, then, to know how to quickly look up alternatives in a pinch.

The image of seemingly endless lines of passengers waiting to speak with a rebooking agent should also cement the idea that air passengers must be the masters of their own fate, and can do so through a mobile device.

Rebooking online saved passenger Ryan Mitchell. He and his family spent Christmas in Austin, Texas, and intended to fly home to Raleigh, North Carolina, on Dec. 26 via Southwest. When their flight got canceled, he decided to drive to the airport to rebook after not being able to reach a Southwest representative by phone — not realizing a nationwide fiasco was unfolding.

By the time he got to the airport around noon, he said in an email, “there was a line a thousand people long.”

Immediately, Mitchell said, he started looking on his phone for other options besides Southwest. He was able to find one on another airline for $350 leaving the same day.

“Bought it as fast as I could,” he said. “Checked prices a few hours later … anything leaving Monday or Tuesday was in the thousands of dollars.”

On Thursday, Southwest said customers affected by flight cancellations or significant flight delays from last Saturday and next Tuesday can submit receipts for consideration via email or on Southwest.com. It also posted a link to a refund request form.

Southwest executives said Thursday that anyone whose flight was cancelled is entitled to a full refund and that the airline would reimburse travel expenses, including tickets on other carriers, rental cars, gas, hotels and meals. Southwest will look at extenuating circumstances case by case. And it will pay for baggage to be shipped to the customer by FedEx or UPS or, in some cases, on a Southwest aircraft.

In a statement Thursday, the Transportation Department said it would use the fullest extent of its investigative and enforcement powers to hold Southwest accountable if the airline fails to adhere to the promises it made to compensate passengers.

But the Southwest executives said the reimbursement process could take several weeks.

So, experts say, flyers should also seriously consider budgeting additional financial resources in the event they must book a night at a hotel or rent a car.

“What are you going to do if the airline can’t save you?” Bangs said. “You have to have the financial resources to get a backup ticket on another airline.”

If possible, Mayerowitz also recommends keeping “a diverse stash” of points and frequent flyer miles across airlines and hotel vendors. Certain credit cards allow users to easily build them up.

“If you have a last-minute funeral, miles can help,” he said. “If hotel rooms are outrageously overpriced, points can help you. So everyone should have an emergency fund, but it should be in points and miles.”

Bangs said situational awareness is also important. Keeping an eye on weather forecasts that may affect your travel plans, and also what alternative destinations may be within reasonable driving distance.

She bemoaned what she called the “learned helplessness” many flyers now experience when they arrive at an airport.

“It can feel like you’re trapped in a netherworld, but you’re not,” Bangs said. “You need to be proactive on your own behalf.”

At least one passenger said she is now rethinking holiday travel altogether. Sallyann Koontz got stuck in Austin after her Southwest Airlines flight home to Charleston, South Carolina, was canceled. She said she would have already rebooked on another airline but found ticket prices had become too expensive — despite price caps meant to ease the burden on travelers.

Next year, she said in an email, she’ll plan differently when it comes to Southwest.

“It has served the public with affordable flights and possibly allowed travel for less affluent families for decades,” Koontz said of the airline. “I would still use them but maybe I would completely avoid holiday travel or believe the horrific weather predictions and cancel my travel plans.”