Southwest Airlines has a few aircraft painted with a special livery such as the U. S. State themed “Maryland One” and “California One” planes. In addition to these state inspired paint schemes, there are a few “Shamu” killer whale themed aircraft of SeaWorld fame. Three Boeing 737 aircraft are coloured in this livery as of this writing.
Registration number N715SW is the Southwest Airlines Shamu plane in the photos below:
The majority of Southwest’s aircraft inventory are in the canyon blue livery: