Americans celebrating their newfound liberty are expected to travel and gather in unprecedented numbers for cookouts, fireworks, and family reunions over the Fourth of July weekend.

However, lingering restrictions, worker shortages, and a large number of unvaccinated people mean that some people may not be as free as they would like to be.

There are also concerns that mixing large numbers of vaccinated and unvaccinated Americans at a time when the highly contagious delta variant is rapidly spreading in the United States may undo some of the progress made against the scourge.

Airlines are bracing for a busy holiday season and have struggled to staff their planes and keep up with the millions of passengers passing through airports. Pools and beaches have been suffering from a lack of lifeguards, and restaurants and bars in tourist areas have had to reduce their hours due to a lack of staff.

President Joe Biden has hailed the July 4 holiday as a watershed moment in the country’s recovery from a crisis that has killed over 600,000 people and resulted in months of restrictions that are now nearly lifted. He intends to host over 1,000 people — first responders, essential workers, and troops — at the White House for a cookout and fireworks to commemorate what the administration is calling a “summer of freedom.”

Vaccines that have been administered to two-thirds of the adult population have resulted in approximately 12,000 new cases and 250 deaths per day in the United States. However, this falls short of Biden’s target of 70% by July 4. Vaccine hesitancy persists, particularly in the Deep South and West, allowing the delta variant to spread across the country. According to AAA, more than 47 million people will travel by car or plane in the United States this weekend, a return to 2019 levels and a 40% increase over last year. There are 3.5 million airline passengers among them.

Travelers at Newark International Airport in New Jersey faced long check-in lines and flight delays on Wednesday, putting their patience to the test. Some passengers were simply relieved to board a plane after their vacation plans were disrupted by COVID-19 restrictions last year.

Rhetta Williams, a 54-year-old pharmaceutical company manager, was on her way to Charleston, South Carolina, for a family reunion with about 50 relatives that had been postponed a year ago due to the virus.

While masks have been removed from public spaces across the country, the Transportation Security Administration emphasizes that they are still required at airports and on planes.

Williams is confident in the efficacy of such safeguards and the shots she received. Zach Carothers, a 21-year-old computer science student, flew from the University of South Carolina to Newark for a weekend at the Jersey Shore, where people have been flocking back since restrictions were eased.

Southwest Airlines offered double pay for flight attendants and other employees who agreed to extra work through Wednesday in order to keep enough workers to meet demand. Southwest and American Airlines unions complained that management did not act quickly enough to retain and retrain pilots following furloughs and retirements caused by the pandemic.

Not everyone is gracefully accepting the ongoing safety restrictions. Airlines are reporting an increase in the number of disruptive passengers who refuse to wear masks.

Fireworks are expected to draw some of the largest crowds in many communities in months.

“I think outdoor stuff is pretty safe for unvaccinated or vaccinated people,” said Dr. Ashish Jha, dean of Brown University’s School of Public Health. “A packed outdoor concert is probably not ideal, but in the absence of that, outdoor activity is safe for people. It’s fine to watch fireworks.”

“With temperatures soaring in many places, I’m worried that more people will move their parties and events indoors, which does pose a risk,” said Dr. Saskia Popescu, an infectious disease expert at George Mason University. In many parts of the U.S., people are becoming too lax about the virus, said Dr. Lynn Goldman. Some states have less than half their population fully vaccinated.