The head of Delta Air Lines — which provided 73% of departures from Salt Lake City International Airport before COVID-19 hit — said Thursday that it will continue to provide social distancing on its flights even though some major competitors are discontinuing that.

“Medical experts we’ve worked with advise that keeping middle seats blocked and limiting capacity makes a real difference in keeping travelers and our people safe on board — and our customers tell us it gives them peace of mind when they fly,” Delta CEO Ed Bastian wrote in a memo to employees.

“That’s why we extended our policy through September, and I expect we will continue to block middle seats beyond that date,” he added. Delta limits its capacity on flights to 60%.

That comes after American and United airlines announced earlier this week that they are discontinuing such steps, and will fill flights to capacity — saying flying at far less than capacity is a business model that cannot be sustained. Also, the chief of United said that blocking middle seats is more of a PR strategy than one to protect safety.

However, others besides Delta also say it’s too early to fill planes to capacity safely. JetBlue is blocking middle seats through at least the end of July, and Southwest said it plans to block them through at least September.

Bastian wrote to Delta’s employees saying he feels the future of Delta depends on it being a leader in protecting the safety of its passengers and workers.

(Francisco Kjolseth | Tribune file photo) Delta Airlines CEO Ed Bastian sits down in an interview to talk about the importance of its Salt Lake City hub on Friday, Jan. 18, 2019.

“With infection rates rising in some parts of the U.S., it becomes clearer every day that our resiliency will rely on our ability to be the leader in safe travel,” he wrote.

That includes requiring passengers to wear masks, and recently forming a partnership with the Mayo Clinic to have it review its cleaning and protection efforts. The airline also is expanding testing of its employees for COVID-19 to soon include at-airport testing in Salt Lake City.

“We’ve been providing testing for both the virus and antibodies at the airport and other facilities in Atlanta, Detroit, Minneapolis and New York,” he said. “Later in July we’ll head to Los Angeles, Salt Lake City and Seattle for onsite testing.”

He said the testing has found positive cases among workers who did not know they were infected. “This important testing will provide baseline data so we can make more informed decisions in the future about protecting your health. We need everyone to sign up – the test takes less than 10 minutes, and it’s crucial to our ability to provide a safe and healthy workplace.”

Bastian noted that the July 4 weekend is typically one of the busiest of the year, but projections show it will still be way down.

“While we’ve seen a small but welcome uptick in volume since the beginning of the COVID-19 pandemic, overall we expect to transport about 600,000 customers for the July 4 weekend – that’s down from 3.2 million a year ago,” he wrote.

“The increases are primarily leisure travelers or those who are flying for essential services. Business travelers, who provide the bulk of our revenue, have not yet returned in significant numbers,” he noted.