Boeing [NYSE: BA] and Ryanair, Europe's largest low-fare carrier, announced that the airline has ordered an additional nine new Next-Generation 737-800s, exercising options from a previous agreement. The deal is valued at upwards of $500 million at list prices.

Five airplanes will be for the replacement of 737-800s in Ryanair's current fleet delivered in 1999 and four will be used to accommodate the airline's continued growth into new markets. Deliveries will begin in September 2007.

Ryanair operates 92 Boeing Next-Generation and Classic 737s. With today's announcement, it now has 239 737s on firm order with an additional 179 options.

"The 737 continues to be the airplane of choice for successful, established low-cost carriers like Ryanair," said Marlin Dailey, vice president of Sales for Europe and Central Asia, Boeing Commercial Airplanes. "You simply can't beat its economics, efficiency and reliability. It's a key ingredient in the recipe for success among carriers around the world."

The new 737-800s will be fitted with Blended Winglets, which will improve fuel efficiency by up to three percent on Ryanair's network, increase range and reduce takeoff noise.