As of this week, U.S. and European Union regulators said they were still reviewing changes Boeing made to 737 Max software after two fatal crashes – this despite the fact that Boeing has said it hoped to resume flights before the end of the year.

Regulators in the U.S. and Europe are still working to determine when the aircraft can resume service: the FAA said this week that it does not have a firm date for completing its review, while American Airlines said it will resume flights with 737 Max jets in January 2020.

Whenever the grounded 737 Max does return to service, will fliers take notice?

People generally don’t have any real make-or-break preferences for aircraft, but that could change. As a May note from Barclays said, 44% of people surveyed said they’d wait a year or more to fly on the 737 Max when it came back. In Europe, the numbers are worse.

So how can you know what kind of plane you’re flying so you can avoid the 737 Max?

First of all, it’s good to know what airlines fly 737 Max planes. The biggest buyers in the U.S. are Southwest Airlines with 34 and American Airlines with 24. United has 14 of the larger 737 Max 9 planes. Air Canada has 24, Norwegian has 18, and Turkish Airlines has 12, and many other airlines operate them as well.

This will change if and when more planes deliver, but Boeing’s website has a list of orders and deliveries by airline. If you’re considering one airline, you can see if the company owns any, though sometimes airlines lease planes instead of owning.

Buying on airline websites

If you’re flying on an airline that flies the 737 Max, you can almost always see what plane you will take when you buy your ticket.

When selecting tickets on Southwest, for example, you can click the flight number and you’ll get a bunch of information, including stats about on-time performance. There is an asterisk, however: “Until the MAX8 aircraft returns to service, Southwest plans to operate MAX8 flights with a different aircraft type,” the fine print reads. “Flight schedules and aircraft type remain subject to change per the Contract of Carriage.”

This likely means that this flight uses the 737 Max if it weren’t grounded, and that a passenger doesn’t have a say if that changes. The contract of carriage for Southwest, which is essentially the terms of use for flying, says the airline “may need to substitute other aircraft” “without prior notice.”

That means if you end up with a 737 Max that you don’t trust, the airline could refuse a refund.

American Airlines’s website similarly shows what plane flies a certain flight.

Google Flights, Expedia, and Kayak

Google Flights shows the aircraft type in the flight details section when you click on a flight’s details.

Click on Expedia’s (EXPE) detail tab. It offers details about aircraft type.

Kayak (BKNG) offers the info as well and even allows users to search by aircraft type if they have plane preferences.

More specific information

If you’re really curious, you can check websites like FlightAware.com to see the recent stats and history about the flight you’re taking.

Some websites like FlightRadar24 can even provide tail numbers for recent flights, which allow you to see even more detail about a plane. Airfleets.net offers information about how old the plane is and its history, provided you know the tail number. The FAA also has a database with registration info and more, if you know the tail number information.

Everything, of course, could change the moment someone arrives at the airport. To find out what kind of plane you’re flying, you can always ask the crew or even look at the tail number if you can see it out the window at the airport.

Popular travel site ThePointsGuy.com adds yet another useful resource for airplane-conscious travelers, and ExpertFlyer.com can offer more information — including seat maps and configurations.

-

Ethan Wolff-Mann is a writer at Yahoo Finance focusing on consumer issues, personal finance, retail, airlines, and more.. Follow him on Twitter @ewolffmann.

The 2020 Social Security increase falls short

Social Security phone scams are now a greater threat than IRS scams

Americans are trying to invest in Denmark’s negative mortgages

‘Flight shame’: A potential headwind for airlines in Europe

Apple Card might finally get people to use Apple Pay

Read the latest financial and business news from Yahoo Finance

Follow Yahoo Finance on Twitter, Facebook, Instagram, Flipboard, LinkedIn, YouTube, and reddit.