Southwest Airlines mustard yellow plastic boarding pass with "Second Boarding Group" and number 37 printed in red on both sides.
Summary:
Boarding Passes
One way Southwest cut costs was by issuing reusable plastic boarding passes and eliminating assigned seating. The passes were sequentially numbered and color-coded for each flight. Passengers boarded in groups in the order in which they checked in. This encouraged early arrivals and speeded up seating, thus allowing Southwest to return an aircraft to service quickly.
