It's time to move on.
Totally understandable that plus-size passengers may face discomfort during flights due to the limited space available on planes. However, there is no universal policy requiring airlines to provide extra seats for these individuals.
Notwithstanding, some airlines may offer larger seats or allow passengers to purchase an additional seat at a discounted rate to ensure their comfort.
For instance, Southwest Airlines has a "Customer of Size" policy that allows passengers who are unable to fit into a single seat to purchase an additional seat at a discounted rate. Delta Airlines also offers "Comfort+ seating," which includes wider seats and additional legroom for a fee.
It is important to note that providing extra seats to plus-size passengers can also have financial implications for airlines, as it means taking additional seats out of circulation that could be sold to other passengers.
Nonetheless, airlines have a responsibility to ensure that all passengers are comfortable and safe during their flights, and should strive to find solutions that balance the needs of all passengers.