Delta Air Lines continues to go against the grain in the US by deliberately capping flight capacity and touting “blocked” middle seats as a distinguishing customer service characteristic.

The Atlanta-based carrier, which has outlined its strategy for rebuilding its long-haul network, said it will look for opportunities to up-size to larger aircraft “on routes where our planes begin to fill” rather than booking flights full. Whereas rivals American Airlines and United Airlines have already started booking flights to capacity where possible and are not blocking middle seats, Delta said in a statement that it will extend “one of our key health and safety protocols this winter holiday season by blocking the selection of middle seats and limiting the number of customers per flight through at least Jan. 6, 2021.”

“Medical experts, including our own partners at Emory Healthcare, agree: more distance on board makes a difference,” Delta chief customer experience officer Bill Lentsch said.

Alaska Airlines, JetBlue Airways and Southwest Airlines are also promoting middle-seat blocks, but those carriers have not yet committed to extending the practice into 2021.

Delta noted that for passengers in parties of three or more, “middle seats will appear as available for booking, to allow families and travel companions to select seats together.” The carrier will also allow customers to book its Delta One business-class cabin on widebody aircraft—which the airline said is “designed with more space and privacy built in”—to capacity from Oct. 1.

Airlines that are not blocking middle seats have said social distancing on aircraft is not possible. Delta CEO Ed Bastian has conceded that capping capacity may cut into the profitability of certain routes, but has emphasized that building back consumer confidence in air travel is a more important goal for the airline industry in the near-term in the face of COVID-19.

A Massachusetts Institute of Technology study looking at the “rough approximation of the risks” of leaving middle seats open on commercial aircraft concluded that doing so does reduce the transmission of the novel coronavirus, but emphasized that the study was just an initial examination of an issue that requires more research.

Photo credit: Delta