Southwest Airlines famously doesn't offer reserved seats, and instead, passengers can select them when they board the plane. However, the airline is blocking middle seats all the way till September 30th. That could be extended if conditions call for it. Originally, Southwest put seat caps through the end of June.
To guarantee social distancing, Southwest is limiting the number of passengers aboard each flight. Southwest isn't the only airline to extend its social distancing policy until late September. Delta Air Lines is also offering encouraging social distancing until September 30, and the carrier is also accomplishing it by only selling window and aisle seats. Meanwhile, JetBlue is guaranteeing that, through at least July 31, you will not sit next to a stranger.
Southwest wants its flyers to be safe from the moment they check in to the moment they disembark the plane. In addition to encouraging social distancing, customer-facing employees must wear masks, snack and beverage service has been streamlined and/or suspended (depending on flights) and planes are cleaned to the most stringent cleaning safety practices.
While social distancing may quell flyers' fears and encourage them to take to the skies again, the International Air Transport Association (IATA) doesn't recommend social distancing. Instead, the IATA recommends that crew members and flyers wear masks as the actual risk of transmission while on board is low. Furthermore, the IATA claims that forced social distancing will, inevitably, result in higher ticket prices as airlines don't make money flying planes that aren't full.
If you are traveling on Southwest with friends or family, don't worry. Those traveling in groups can still choose to sit together.