In the wake of this week’s unprecedented wave of US flight cancellations, experts and passengers alike are weighing how travelers can best prepare for a disrupted itinerary.

While multiple explanations have been put forward to account for the chaos that has stranded thousands of passengers in recent days, most of which was led by Southwest Airlines and included weather, staffing and technology issues, there should be one key takeaway, they say. The experts. : Travelers can no longer trust their airline when something goes wrong and instead must have the intelligence and, where possible, the financial resources to take matters into their own hands.

«Gone are the days when you could 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 familiarize themselves with sites like Google Flights, in case they need to look for an alternate flight, he said. Some airlines, including Southwest, no longer have automatic agreements that allow 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 fewer options, said Scott Mayerowitz, executive editor of travel site The Points Guy. The most important thing, then, is knowing how to quickly look for alternatives in a pinch.

The image of seemingly endless lines of passengers waiting to speak to a booking change agent should also cement the idea that air travelers should be in control of their own destination and can do so via a mobile device.

Online booking change saved passenger Ryan Mitchell. He and his family spent Christmas in Austin, Texas, and intended to fly to Raleigh, North Carolina, on December 26 via Southwest. When his flight was cancelled, he decided to drive to the airport to rebook after failing to reach a Southwest representative on the phone, not realizing a nationwide fiasco was unfolding.

When he arrived at the airport around noon, he said in an email, «there was a line of a thousand people.»

Immediately, Mitchell said, he began looking on his phone for options other than Southwest. He was able to find one on another airline for $350 that left the same day.

«I bought it as fast as I could,» he said. «I checked the prices a few hours later…anything that came out on Monday or Tuesday was going for 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 E-mail or in southwest.com. Also posted a link to a refund request form.

Southwest executives said Thursday that anyone whose flight has been canceled is entitled to a full refund and that the airline will reimburse travel expenses, including tickets on other airlines, rental cars, gas, hotels and meals. Southwest will consider extenuating circumstances on a case-by-case basis. And you’ll pay for shipping the bag to the customer via FedEx or UPS or, in some cases, on a Southwest plane.

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

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

Therefore, experts say, travelers should also seriously consider budgeting for additional financial resources in case they need to book a night in 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 frequent flyer points and miles across all airlines and hotel providers. Certain credit cards allow users to accumulate them easily.

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

Bangs said that situational awareness is also important. Keep an eye out for weather forecasts that may affect your travel plans and also for alternative destinations that may be within a reasonable driving distance.

He lamented what he called the «learned helplessness» many travelers now experience when arriving at an airport.

«It might look like you’re trapped in an underworld, but you’re not,» Bangs said. «You have to be proactive on your own behalf.»

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

Next year, he said in an email, he will plan differently when it comes to Southwest.

«It has served the public with affordable flights and possibly allowed less wealthy families to travel for decades,» Koontz said of the airline. «I’d still use them, but maybe I’d avoid vacation travel altogether or believe the dire weather predictions and cancel my travel plans.»