Delta Air Lines Inc. plans to use clean cabins to boost customer satisfaction and attract a larger portion of people who still fly, aiming to reduce the cash it burns daily to zero by year-end.

The airline will work for a Net Promoter Score of at least 65 in the second half, 15 points above Delta’s average performance last year, Chief Executive Officer Ed Bastian wrote Thursday in a memo to employees.

”We hear from customers every day, telling us that they are switching their loyalty to Delta because of the safety practices we have in place, and the care we take to ensure cleanliness and comfort,” he said.

Net Promoter is a program to measure customer experience and satisfaction that is widely used by airlines, hotels and others. Delta’s score was 70 in July, Bastian said.

“Achieving this level of customer satisfaction will help bring in the additional revenue we need to reduce our cash burn,” Bastian wrote. “It also will build additional loyalty and affinity for our brand, which will power our growth when demand begins to come back.”

Atlanta-based Delta has reduced operating expenses by half since the pandemic decimated airline revenues globally, burning $27 million in cash daily in June, he said, down from $100 million a day in March. About 20% of Delta’s workforce left the company by Aug. 1 through retirement and voluntary leave packages, helping to cut spending.