DALLAS (January 21, 2013)—Dallas-based Southwest Airlines has added a $40 pay-at-the-gate option for travelers with cheaper tickets who want to be among the first to group to board.

Southwest doesn't offer assigned seats and the carrier Monday announced the latest option for coveted group "A'' boarding.

The boarding slots for cheaper tickets are assigned based on when a person checks in for the flight.

Business select fares cost the most but are refundable and include priority boarding, but other passengers can pay extra to reserve a boarding spot right behind elite fliers.

The latest plan offers passengers the chance to buy one of the earliest boarding positions for $40 per flight.

The offer begins 45 minutes before the flight departs.

Passengers will hear an announcement at the gate if the slots are available.