U.S regional carrier Southwest has implemented an assigned seating policy.

Previously, passengers could sit in whichever seat was available, but from January 27th they had to sit in the seat they were allocated, or they would have to pay a fee to chose their position on the aircraft.

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The move puts the carrier in line with the majority of airlines worldwide. Most LCCs ditched non-assigned seating around 15 years ago when systems to improve turnaround times became readily available.

As is common practice across the industry, passengers are split into groups, in Southwest’s case, eight of them. Priority groups get to board first, with basic fare passengers arriving in the aircraft last.

However, assigned seating is not popular with all passengers. Previously, overweight passengers who couldn’t fit in one seat without encroaching on others could have requested to be sat next to an empty seat for no extra cost. Now they will have to pay for that seat at the time of booking.