Few conditions for travelers are as insidious as jet lag. 

The experience can be worse than the worst hangover of your life, trigger nightmares, headaches, dry mouth, and worse. And yet according to one well-spoken industry expert, airlines finally may have figured out how to soften the effects.

That expert, George Hobica, president of AirfareWatchdog.com, penned a recent article for USA Today in which he explained how new materials in new aircraft from a duo of plane manufacturers actually work to minimize jet lag. The gist: Old aluminum planes are bad, new equipment made of carbon-reinforced plastic composites are better.

In the article, Hobica noted that two models in particular—the Boeing 787 Dreamliner and the Airbus A350—are made with these newer materials and work really well to help passengers arrive at their destinations feeling refreshed. He added that there are websites (here and here, respectively) for passengers to see which carriers fly these planes and where, in the event that passengers wish to book accordingly. 

As Hobica explained in an exclusive interview this week, “jet lag” really is a combination of altitude sickness and dehydration. 

“When you look at the research on this, the symptoms of jet lag are the same as the symptoms for something called ‘Acute Mountain Sickness,’” he explained. “The effects are more pronounced the older you are.”

With this in mind, there are two reasons why newer planes seem to mitigate jet lag: the perceived altitude that results from pressurization, and the presence of more moisture.

The first concept is more complicated than the second. Most commercial airplanes fly around 35,000 feet—an altitude at which humans could not survive without additional oxygen. To eliminate this problem, most airplanes pressurize the cabin to create a perceived altitude of about 8,000 feet. This means airplanes create an environment that feels the same way it would feel if you were standing 8,000 feet above sea level. The air is thinner. It’s dry. If you’re used to living closer to sea level, the experience might even give you a headache. 

In short, prolonged exposure to these conditions makes you feel lousy. But the new planes are able to pressurize cabins to create a perceived altitude of about 6,000 feet—an altitude at which some of the conditions aren’t as significant.

“You might not notice the difference on a six-hour flight, but on a 15- or 18- or 19-hour flight, you notice it,” Hobica said. 

More moisture in the passenger cabin also contributes to diminished effects of jet lag.

Hobica noted that older airplanes were made of aluminum and other metals that can corrode, materials that don’t do well when exposed to water. For this reason—to minimize risk, really—the pressurization process historically has reduced the moisture content to around 1 percent humidity. This is why airplane air is so darn dry.

Newer planes, however, are made of carbon-reinforced plastics—material that doesn’t care if it gets wet. According to Hobica (and a bunch of research), this reality allows for more humidity into the cabin after pressurization, making it much more comfortable for us humans. 

“Eventually, all planes will offer the same benefits as the newer ones, but it will take a few decades,” said Hobica. “Years from now the experience should be more pleasant for all of us.”

What do we leisure travelers do until then? According to Hobica, lubricating nostrils, drinking water, NOT drinking alcohol, and flying with eyeshades can make flights more comfortable. Of course, you also can opt to do nothing and make the most of your jet lag, as one of our writers explained back in 2015. At least you now know a little more about what’s really happening.

 Matt Villano is a freelance writer and editor based in Healdsburg, California. In nearly 20 years as a full-time freelancer, he has covered travel for publications including TIME, the Wall Street Journal, the New York Times, Sunset, Backpacker, Entrepreneur, and more. He contributes to the Expedia Viewfinder blog and writes a monthly food column for Islands magazine. Villano also serves on the board of the Family Travel Association and blogs about family travel at Wandering Pod. Learn more about him at Whalehead.com.