Many of the first cases, however, were travel-related. The first U.S. case was Jan. 21 in Washington state, where a man had returned from Wuhan, China, the epicenter of the outbreak. Georgia’s first cases, reported March 2, were also travel-related. A father and son had tested positive from the virus after returning from Italy, where coronavirus cases were exploding.

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A day after the airline industry's pronouncement, President Donald Trump announced tight restrictions on travel from Europe and the State Department issued a Level 3 travel advisory urging U.S. citizens to reconsider travel abroad.

Within a week, passenger counts had dropped 50% from last year.

The AJC’s analysis found that passenger volume had begun to decline in early March even as the number of flights remained constant with the prior year.

Many U.S. companies, acting ahead of President Trump’s European travel ban, were among the first to recognize the risk of air travel and directed their employees to stop international and non-essential travel in early March.

“Once that happened, the leisure travelers were the only ones still going and purchasing tickets because they just don’t know any better,” said Charlie Leocha, co-founder of consumer advocacy group Travelers United.

Bill McGee, aviation adviser for Consumer Reports, the nonprofit consumer watchdog magazine, said it was “dangerous” for the airline industry to have been promoting flying into mid-March.

Richard Rothenberg, an epidemiologist in Georgia State University’s School of Public Health, said earlier restrictions probably would have made a difference slowing the spread of the virus, but it’s impossible to say how much.

“Anything that reduces human contact is going to have an impact,” he said. “If you have a certain probability of coming into contact with someone who is infectious or can transmit the virus, by whatever means, then you have a certain probability of contracting it. The less contact you have, the lower the probability.”

Rothenberg said history shows that past outbreaks, such as SARS in 2003 or MERS 2012, spread rapidly through international travel. But COVID-19 is new and there has not been enough available testing to say what role travel restrictions, particularly within the U.S., play in arresting the spread of the disease.

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“What really is important to know, which we don’t know, is if somebody is on a flight and there are 200 other passengers on the flight and this person is infected, what is the probability of transmitting that infection to other people on that flight,” he said. “That’s critical information to have in trying to understand both the intraflight and subsequent spread of disease, and it’s not a piece of information we have right now.”

Nancy McGehee, head of Virginia Tech’s hospitality and tourism management department, said it was unreasonable to expect airlines to have sophisticated knowledge about spread of the virus “without any guidance or a uniform policy.”

A nearly empty Hartsfield-Jackson International Airport on Thursday April 9, 2020. The AJC’s analysis found that passenger volume had begun to decline in early March even as the number of flights remained constant with the prior year. (JOHN SPINK/JSPINK@AJC.COM) Credit: JOHN SPINK / AJC Credit: JOHN SPINK / AJC

In a statement to the AJC, Airlines for America said last week that the top priority of U.S. airlines is “the safety and well-being of our passengers and employees.”

“Since the early stages of the outbreak, U.S. carriers have worked to increase communications with passengers and implement travel policies, and remain committed to making accommodations that are responsive to travelers’ needs,” a spokeswoman said.

Planes fly, but no passengers

Today, flights in and out of Hartsfield-Jackson are down 65% from last year, and passenger volumes are down 95%, according to the AJC’s analysis. The 300,000 to 320,000 passengers that once passed through the terminals have slowed to a trickle.

Airlines have continued to operate flights, as some people still need to travel, including health care workers, people who need to travel for vital medical treatments and others. Air cargo has grown, as demand for supplies and deliveries drives more air freight traffic.

Another reason airlines continue to fly is Congress and the Trump administration want them to.

In order to qualify for aid under the federal stimulus bill, airlines also must maintain service to virtually all the points in the United States they previously served. That means flights on many routes will continue operating even if there are few passengers flying and planes are mostly empty.

Concessions International, which operates restaurants at Hartsfield-Jackson, has felt the drop-off, laying off nearly 300 employees, said CEO Donata Russell Ross.

“I personally believe in safety before everything else, so for me I have no problem with the stay-at-home orders,” said Ross.

But, she added, “we are suffering greatly for it.”