No airline in the world operates more Boeing 737s than Southwest Airlines.

The Dallas-based airline is well-known for exclusively operating the type for nearly all its 51-year history. A common and consistent fleet not only is easier for the airline to manage, it’s become a staple of the Southwest brand.

Southwest currently operates an active fleet of 718 737s of various models with an average age of 12.7 years, according to Planespotters.net. The airline plans to add more; as of April, Southwest has nearly 450 newer 737s on order with options for 183 more to modernize its fleet.

The most prominent model—and also the smallest—in Southwest’s fleet is the 737-700, with more than 400 of them in operation. This picture of a 737-700 taking off from Reading Regional Airport was shared with us by Ethan Minnich.

Southwest also uses the larger 737-800, and it is expected to take delivery of newer generation Boeing 737 MAX 7 and 8 aircraft through the rest of the decade. Those models save fuel and reduce noise and emissions.

At Pittsburgh International Airport, multiple Southwest 737s can regularly be seen lined up on Concourse A late at night or in the early-morning hours. Add in a beautiful sunrise and you can’t ask for a prettier view, as Scott Michalism demonstrates below.

Thanks, Ethan and Scott!

Our readers continue to pass along shots of unique aircraft, international airports, historical events, gorgeous views and even family vacation photos for this feature. We love them! Keep them coming—you can click here for submission guidelines.

A row of Southwest 737s lined up at Pittsburgh International Airport during an early morning sunrise. (Photo submitted by Scott Michalism)