Delta Air Lines Inc. may extend its coronavirus-era policy of leaving middle seats vacant on its flights even as other carriers go back to booking full planes.

“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,” Chief Executive Officer Ed Bastian said in a memo to employees Thursday. “That’s why we extended our policy through September, and I expect we will continue to block middle seats beyond that date.”

Delta’s plan underscores an emerging divide among carriers about the value of separating passengers as a precaution against the spread of the coronavirus. American Airlines Group Inc. resumed selling seats to full capacity Wednesday, saying it’s impossible to effectively social distance in flight and that masks and new cleaning methods have stepped-up protection. United Airlines Holdings Inc. never pledged to keep seats open.

Greater Caution

Southwest Airlines Co., however, is only booking planes two-thirds full through September and JetBlue Airways Corp. also is blocking middle seats.

Carriers also have stepped-up cleaning of aircraft and airports and most are requiring travelers wear face masks in gate areas and during flights. Some have said it’s not financially feasible to block seats longer term.

Carriers worldwide have been battered by a collapse in demand as the coronavirus spread in March, triggering government-imposed restrictions on travel. While consumers recently have begun booking vacations following months in quarantine, more lucrative business travel isn’t expected to fully return until as late as 2023.

Delta will fly about 600,000 customers over the upcoming July 4 holiday weekend, compared with 3.2 million a year earlier, Bastian said.