Delta Air Lines announced Wednesday that they will no longer block middle seats on their flights starting May 1, ending the longest holdout of the last major U.S. airlines to continue the policy.

"While Delta’s decision to block middle seats has given many customers a reason to choose Delta over the past year, the signature hospitality of our employees and the experiences they deliver to customers every day have also deepened their trust in our airline," CEO Ed Bastian said in a statement.

"The relationships we’ve built, together with the knowledge that nearly 65 percent of those who flew Delta in 2019 anticipate having at least one dose of the COVID-19 vaccine by May 1, are what’s giving us the assurance to offer customers the ability to choose any seat on our aircraft, while also introducing new services, products and rewards to support the journey," Bastian continued.

Delta began blocking middle seats in April 2020, and kept the policy going longer than any other major U.S. airline. The company said that their surveys showed about 65% of the company's pre-pandemic passengers would have at least one vaccine dose by May 1, but Bastian noted that safety measures will continue.

"Don't confuse these actions with a return to 'normal,'" Bastian said in a memo to employees Wednesday. "We're still operating in a pandemic, and many of the changes we've made over the past year, such as strengthening our cleanliness protocols and eliminating change fees, will be permanent. Importantly, masks remain critical to our ability to safely welcome more people onboard our planes, and we remain committed to enforcing these requirements."

Other airlines reopened middle seats for purchase last summer.

This is a developing story. Check back later for further updates.