Fliers in the United States have gotten used to bringing their own food, but now they'll have to bring their own beverages, too.

Major US airlines are implementing substantial changes to the few free things passengers still receive on airplanes, including drinks and snacks, because of the coronavirus pandemic.

Delta Air Lines, Southwest and American Airlines have all announced this week that they're temporarily suspending beverage service and cutting meal service as way to cut costs and reduce the number of items flight attendants touch.

The changes, which seemed unthinkable just a few weeks ago, are the latest change for the beleaguered industry that has dealt with plummeting revenue, strikingly empty flights and the need for government assistance just to survive the year. Some in the industry are calling for domestic flight operations to be temporarily shut down.

Here's what fliers will notice:

American Airlines

Beginning March 27 and for the following month, flights on American that are shorter than 4.5 hours will no longer serve meals in first class. Snacks and food available for purchase in the main cabin have been canceled. And beverages will be available only upon request. It also will no longer sell alcohol in economy, but will continue to serve it in first class.

American is making fewer changes on its long-haul flights, of which there are fewer, anyway, because of travel restrictions from other countries. Separately, American has shuttered a number of its pre-flight lounges and is no longer accepting checked pets.

To encourage social distancing policies recommended by the Centers for Disease Control and Prevention, American is reassigning seats to customers so they don't have to sit next to someone else. That means most people will be able to avoid the dreaded middle seat. The changes were made easier because many airlines are flying with only 20% to 30% of seats filled.

Delta Air Lines

Beginning immediately on domestic and some shorter international flights, Delta is reducing the number of snack offerings to two, giving its first class passengers boxed meals and completely eliminating alcoholic drinks for everyone. The only beverage available to order is bottled water. The changes are in addition to eliminating glassware and hot towels in first class.

The airline said it's currently "evaluating adjustments" for its long-haul international flights. A number of its pre-flight lounges, known as the Sky Club, have also been closed because of dwindling passenger traffic.

Southwest Airlines

Southwest  doesn't have first class cabins or lounges, but it's also making changes. It's suspending beverage and snack service beginning Wednesday to "limit close public interactions" between customers and its crew. Canned water will be made available by request.

United Airlines

United told CNN Business that it doesn't have immediate plans to make changes similar to its rivals. It has tweaked how its offering snacks by serving them on a tray instead of letting passengers pick their own, no longer refilling beverages and letting their flight attendants wear gloves during flights.