Ryanair, Europe's largest low-cost carrier, took delivery on October 26 of its 150th Boeing Next-Generation 737-800.

Shown in the picture, the 146th, 147th, 148th, 149th and 150th 737s for Ryanair are parked in formation at Boeing Field in Seattle, where they underwent flight-testing prior to delivery to Ryanair.

The successful European carrier operates a fleet of 737-800s around Europe and northwest Africa.

From its inception, Ryanair has relied on the 737 - first the 737 Classic and now the Next-Generation 737 - to help it meet strenuous efficiency, environmental, cost and reliability targets that are critical to the success of its business model.

Ryanair has replaced all of its older 737 Classics with the newer Next-Generation 737 and has achieved a 50 percent reduction in CO2 emissions per passenger kilometer since 1998.

An additional 121 737s remain to be delivered to Ryanair.

The last 737 Classic was phased out in January 2006.

Ryanair operates the second largest 737 fleet in the world, after Southwest Airlines in the United States.