Faced with widespread outrage from Democratic lawmakers, Frontier Airlines said late Wednesday it was abandoning its plan to sell passengers a $39 upgrade that would guarantee they could sit next to an empty middle seat while flying during the coronavirus outbreak.

Prominent Democrats on Capitol Hill had criticized the program, scheduled to start Friday, saying it was taking advantage of people's fear during the pandemic.

And late Wednesday night Frontier Chief Executive Barry Biffle did an about face, outlining the reasons for the change of course in a letter to three Democratic lawmakers that the company also shared with The Washington Post.

"We recognize the concerns raised that we are profiting from safety and this was never our intent," Biffle wrote. "We simply wanted to provide our customers with an option for more space. However, we will rescind the seat price increase associated with the More Room product and revert to our former seat assignment pricing."

Airlines have been grappling with how to keep passengers and their employees safe during the pandemic. Many have taken steps to spread passengers out onboard, but Frontier stood out for offering guaranteed social distancing as a paid-for upgrade.

At a hearing of the Senate Commerce Committee on Wednesday, the head of a major airline trade group that doesn't include Frontier, said he couldn't imagine other airlines following suit.

Air passenger numbers have declined more than 90 percent in recent weeks as international travel has been restricted and most states have implemented stay-at-home orders. But in his letter, Biffle said Frontier was starting to see its planes fill up again.

"Social distancing becomes more problematic as flights fill up and, therefore, we chose to require face masks for everyone," Biffle wrote. "While we believe this ensures safety, we knew some customers wanted more peace of mind and therefore we introduced the More Room product that guaranteed an empty middle seat."

While airlines are content now to let passengers spread out when there's so few of them, industry leaders recognize that won't be sustainable long-term. Leaving middle seats empty, for example, means losing close to a third of available space. Biffle made that point in his letter, saying it would cause ticket prices to rise 50 percent.

"This would not only be harmful to consumers but would cause further strain on the economy at a time when our country can least afford it," he wrote.

Biffle was responding to a letter sent earlier Wednesday by Reps. Jesús "Chuy" Garcia, D-Ill., and Steve Cohen, D-Tenn., and Sen. Edward Markey, D-Mass. The lawmakers, who have sponsored legislation that would prohibit airlines from charging unreasonable fees, called the proposal "outrageous."

"The flying public should not be charged extra to stay healthy on flights," they wrote.

García said he was glad to learn Frontier was giving up on the plan. “Health and safety, as well as the mitigation of the spread of COVID-19 must be our top priority — not nickel-and-diming passengers who want to maintain social distancing in their seating arrangements,” he said late Wednesday, via a spokeswoman.

“During these challenging times we must all act responsibly and put the health and safety of the American public above profits,” García said. “I understand that airlines are deeply impacted by this crisis, but price- gouging customers is not the solution.”