American Airlines will start selling middle seats again as airlines bet that customers won't care about social distancing in flight

• American Airlines said it will stop blocking middle seats and limiting capacity on its flights, potentially ending social distancing on planes.
• Other airlines, including United and Spirit, also do not limit capacity, while Delta has said it will do so through September 30.
• American will still require masks on board, and said it will expand its disinfection initiative on planes. It will also allow customers to switch to an emptier flight, if possible.

It may be a little bit harder to snag an empty middle seat next to you on your next flight.

American Airlines said on Friday that it will stop blocking middle seats on its flights starting on July 1.

The airline had been limiting capacity on flights and blocking passengers from choosing middle seats in the name of social distancing since April.

However, as travel demand begins to pick back up, the airline said it will begin filling those flights to capacity, if enough people buy tickets.

American is not the only carrier filling its flights. United will sell every seat on board, and has argued that social distancing is not possible on planes, Spirit, Frontier, and other low-cost-carriers have also continued to fill their planes.

Delta, however, has said it will cap flights at until at least the September 30, blocking middle seats in economy, and every other seat in first class. The airline has said it will add additional flights to routes where demand outpaces the limited capacity.

According to American, the airline is taking other safety measures to reduce the risk of COVID-19 transmission on board. Those measures include mandatory masks on board, newly implemented cleaning and disinfection procedures, and requiring passengers to complete a health self-assessment before flights.

American appeared to be the first airline in the US to ban a passenger for refusing to wear a mask earlier this month.

Airlines and industry representatives, including the International Air Transport Association, have argued that social distancing on flights is not necessary, due to air flow patterns on planes, High Efficiency Particulate Air (HEPA) filters that prevent microbes in the air from recirculating, other cleaning measures, and the use of masks.

However, as airlines try to accelerate the recovery of travel demand, some airlines are likely to use blocked seats, branded cleaning procedures, and more as a brand differentiator, according to Shashank Nigam, CEO of aviation strategy and marketing firm SimpliFlying.

Others may determine that they will be more successful selling those blocked seats instead of flying with them empty.

American said it will notify customers when their flights are starting to fill up and allow them to move to an emptier flight, where possible. The airline also extended its flexible travel waiver for travel through September 30.

The airline plans to fly 55% of the previous year's domestic capacity in July — up from just 20% in April, and 25% in May.