Source: Harriet Baskas , NBC News ( Free Registration )

Southwest Airlines, known for open seating and boarding passengers in bunches, announced this week that fliers can buy a priority spot in boarding group "A" for $40 per flight.

Southwest will put unsold slots in the A1-15 boarding group up for sale, when available, at the gate beginning 45 minutes before departure. Passengers will then be able to use a credit card to buy an early boarding spot. The airline tested the program in San Diego in December and received positive feedback.

Read Full Article: Southwest fliers can board early—for $40