On Monday, airlines reinstated a slew of flights between the U.S. and the U.K., as the U.K. announced its plans to reopen to vaccinated Americans.

But the announcement came as fears mount about the highly contagious delta variant, the dominant strain of COVID-19 spreading across the U.S., leaving many to question their summer trips.

Here's what two infectious disease experts had to say about how safe it is to take that vacation:

On average, more than two million people are being screened daily at U.S. airports, according to the Transportation Security Administration. But that doesn't mean you're sure to get infected at a crowded terminal.

"I think airports tend to be one of the safest locations given the recommendations that are in place about mask wearing in the airport and on airplanes," Dr. Colleen Kraft, the associate chief medical officer at Emory University Hospital, told ABC News. "You should be able to avoid transmission if everyone around you is wearing a mask and you're wearing a mask."

Kraft recommends taking outdoor vacations in places where you have space and can easily keep your distance from others.

PHOTO: A Transportation Security Administration (TSA) agent guides travelers at a checkpoint in the Detroit Metropolitan Wayne County Airport (DTX) in Romulus, Mich., June 12, 2021.
Matthew Hatcher/Bloomberg via Getty Images, FILE.
A Transportation Security Administration (TSA) agent guides travelers at a checkpoint in the Detroit Metropolitan Wayne County Airport (DTX) in Romulus, Mich., June 12, 2021.

"We chose to go to Yellowstone and Grand Teton," she said. "We didn't know what the state of the pandemic was going to be this summer, so we wanted to do a national park, an outdoor thing like rafting, kayaking -- things that were high ventilation and minimal people."

Dr. Anne Rimoin, an epidemiology professor at the University of California, Los Angeles, said whether or not it's safe to travel also very much depends on your vaccination status.

"If you're vaccinated, you yourself do not have to be worried about getting really sick, getting hospitalized and dying is a very unlikely scenario," she said. "If you are unvaccinated, you do have to really consider this."

But it's not a one-size-fits-all kind of scenario.

"Everybody has to think about what their risk tolerance is and just act accordingly," Rimoin said. "It's important to remember that the evidence is mounting that even if you are vaccinated, you can get infected with this virus and spread it to other people."

PHOTO: People wait in line at a Miami-Dade County COVID-19 testing site, Monday, July 26, 2021, in Hialeah, Fla.
Lynne Sladky/AP
People wait in line at a Miami-Dade County COVID-19 testing site, Monday, July 26, 2021, in Hialeah, Fla.

If you are going on a trip soon, the epidemiology professor recommends wearing a mask indoors -- even if there isn't a mask mandate in place -- washing your hands and distancing from other people.

"If I were traveling, I would get a KN95," she said. "They provide a lot more protection. They fit much better. And if you don't have those, you can double mask, and really make sure those masks are fitting you well because that's going to make a very big difference."

Rimoin's last vacation was over the July 4th holiday.

"If I had a trip, I would go," she said. "I would just be a lot more thoughtful about what I was doing and then when I got back, I would probably get tested to make sure that I didn't have a breakthrough infection and maybe wait to see my mom, or somebody who's older for a week or two just to be sure that I was safe. It doesn't mean that you have to completely stop living your life."