The coronavirus pandemic brought air travel to a screeching halt. And while the pandemic was plenty brutal for the industry, it also brought some silver linings. Among them: better airline change and cancellation policies.

Airlines began offering flexible travel policies to help with the ensuing uncertainty. And since then, airlines have iterated on those change and cancellation policies, with some more generous than others. Southwest has always stood out (and it continued to get better by removing expiration dates on its flight credits). Meanwhile, some airlines that were generous in the first few years of the pandemic have since reverted to their old ways.

Here we’ve rated the flexible booking policies for eight major U.S. airlines on several criteria, and ranked them from most flexible to least. We’ve also included some tips for when, how and whether to book your upcoming flights:

Airlines with the best flexible travel policies

If you have the option to book future air travel with several airlines, here are our current rankings of which ones offer the most flexible policies:

These rankings are based on the policies outlined below. For many travelers, even the more restrictive policies will still offer plenty of value, so compare this table against your own travel plans and uncertainties.

Tips for booking

Book directly through the airline. Generally, using a third party like Expedia, Orbitz or a credit card rewards portal is a fine alternative to purchasing directly through the airline. However, as anyone who has tried to deal with these online travel agencies this month can tell you, it adds an extra layer of uncertainty and customer support wrangling for changes and cancellations.

Canceling a ticket doesn’t mean you get your money back. Most airlines issue a credit for canceled bookings that can be used for some amount of time (often 12 months) after the cancellation. So you shouldn’t book a dozen flights for this year assuming you can cancel them and simply get your money back.

Award flights (using miles) have the same flexible policies as cash flights. And booking last-minute one-way flights with miles is often a good strategy.

Industry-wide airline policies

Airline ticket policies range across companies, but there are a few standards to count on.

Basic economy

In most cases, basic economy fares cannot be changed or canceled for free on any airline. This means that these fares should be avoided outright by any traveler who is not completely confident in their plans. As a rule of thumb, they are the least-refundable airline tickets.

“Free” cancellations

Just because a fare can be canceled without incurring a fee does not mean you will get your money back. In most airlines, in most cases, canceling a flight will result in receiving a voucher or credit with the airline. These vouches are also fairly limiting in that they usually have expiration dates (one year from issue date is common). Notable exceptions include Southwest Travel Funds, which do not expire.

What does this mean? Travelers shouldn’t book several flights, planning to cancel all but the one they expect to take. Doing so will result in receiving a large sum of expiring credits on a specific airline.