Southwest Airlines is backtracking on one of its policies after requiring passengers who couldn’t fit within the armrests of their seat to pay extra. Earlier this year, the airline said that plus-sized travelers had to “proactively” buy an additional seat for their flights, with the company deciding “in its sole discretion" to force the issue for the sake of customer safety and comfort concerns. The move sparked immense backlash at the time from travelers who called the policy a “fat tax.” Now, Southwest is walking that rule back , no longer requiring plus-sized passengers to purchase an extra seat in advance. “On flights where adjacent seats are available, our Agents at the airport are empowered to provide an additional seat at no extra cost to Customers who require one,” the airline said in a Friday statement to The Independent .…