Some of the nation's top public health experts tell the NBC4 I-Team that they would wear masks in most venues on a vacation, even if they're not required.
COVID cases are up more than 50% nationwide in recent weeks, but masks are currently not required in most places you frequent on vacations -- airplanes, most airports, trains, museums.
"I do personally prefer to be wearing a mask when traveling. It's hard to know who you're going to come into contact with or what you might be exposed to when you're in public transport," says Professor Kristen Choi of UCLA's Fielding School of Public Health, who recently masked up on flights to and from Costa Rica.
In fact, three out of four top public health experts told the I-Team they'd always wear a mask on a plane, even though it's no longer required.
Dr. Amesh Adalja of Johns Hopkins Bloomberg School of Public Health, says he's less concerned about planes than other settings.
"The air is exchanged at a very high rate on planes, where it's HEPA filtered. Flying is probably one of the lower risk things that I do versus going to a Starbucks and sitting there reading without a mask on," says Dr. Adalja.
In fact, a report from the U.S. Department of Defense (DOD) said the air is exchanged in the cabin of planes more than 30 times an hour; that's even more than in sterile hospital operations rooms, where it's exchanged 12 times an hours through filtration systems. [link to full DOD report]
However, all four experts consider crowded airports a much higher risk environments, where masking up is prudent even in cities when it's not required.
"I still use a mask if I'm going to go into a crowded, indoor space … including airports and jetways," Dr. Robert Kim-Farley of UCLA's Fielding School of Public Health told NBC4.
"We are not out of the woods with COVID. I think it's still potentially going to show us a lot more surprises," Kim-Farley said.
The I-Team observed thousands of travelers at LAX and Hollywood Burbank Airport not wearing masks in the terminals, like Jaime Reyes who was flying Burbank to Oakland.
"I didn't know they required masks at this airport. It's very confusing. When did they change?" Reyes said.
Numerous travelers told the I-Team they were confused about LA County's constantly changing airport mask mandates.
The county first required masks inside airport terminals in May 2021, then lifted the mask mandate this March, then abruptly reinstated it on April 22.
The I-Team asked LA County's Public Health Director Dr. Barbara Ferrer why there isn't tougher enforcement of the airport mask mandate, and her answer was vague.
"We are working with both airports in LA County. We are particularly focused on making sure that employees are wearing their masks," said Dr. Ferrer.
"If you don't think you need to do this [wear a mask] for yourself, I really encourage people to do it for other people." Ferrer added.
The I-Team reached out to LAX and Hollywood Burbank Airport about the lack of mask wearing. LAX didn't respond. A spokesperson for Hollywood Burbank said "Compliance or non-compliance with the county's mandate-as with any rule or regulation-is up to the individuals."
The bottom line from our experts, if you're near crowds of strangers on your summer vacation, it's better to mask up than get COVID.
"I will be wearing a mask in my Uber to the airport, in the airport while I wait, and on the plane as I travel," says critical care nurse and former medical school instructor Alice Benjamin, who has treated COVID patients the entire pandemic.
"I err on the side of caution and I wear a mask, indoors and outdoors on vacation. And that's just because I'm in close quarters with people that I don't know. Have they been vaccinated? Do I know their COVID status? If I don't know those things, I wear a mask," Benjamin said.