US airports see surge in travelers during Fourth of July holiday weekend

San Francisco's airport is one of many packed full of holiday weekend travelers. It's expected to resemble pre-pandemic numbers and even be one of the busiest weekends ever.

About 47-million people are expected to travel in some form this 4th of July weekend; AAA reports more than three-million will do so by plane.

On Friday, TSA reported via a tweet about 2.1 million Americans checked in through security at U.S. airports. Numbers like that are getting the attention of infectious disease specialists, considering the rising COVID-19 Delta variant.

"A lot of noses and mouths together," said Dr Peter Chin-Hong of UCSF.

"In a group of mixed vaccinated and unvaccinated folks from areas of the country that have different levels of circulating virus."

He says disease likely wouldn't spread on the plane, but likely at checkpoints on the way to your flight.

"Like standing in the TSA line, feeling hot and you take your mask off for a little bit, or going to the food court and you're just running around getting snacks before the flight."

Masks are still required on all forms of transportation including planes, regarding of vaccination status. Dr. Chin-Hong says the best defense against the COVID-19 Delta variant is a COVID-19 vaccine.

"You know you're not going to get sick," he said. "You're not going to go to the hospital, and you're certainly not going to die if you get vaccinated."