Alaska Airlines' fleet of fuel-efficient Boeing airplanes is growing with the purchase of six Boeing 737-900 Extended Range aircraft, valued at $594 million, Boeing's current list price. The new planes, four scheduled for delivery in 2016 and two in 2017, bring Alaska's total jets on order to 79.

"Alaska's confidence in the 737-900ER is something that everyone at Boeing takes great pride in," said Boeing Commercial Airplanes President and CEO Ray Conner. "As hometown partners, Alaska and Boeing have a shared vision to put the most innovative and fuel-efficient airplanes in the skies. The 737-900ER is a testament to that vision."

Alaska is transitioning to Boeing's most modern and efficient Next-Generation 737s. Over the next few years, Alaska's remaining 737-400s will be replaced with 737-900ERs, which transport 25 percent more passengers on the same amount of fuel.

"We're delighted Boeing is able to expedite delivery of four of these new 737-900ERs, increasing the number of planes we'll receive next year to 19," said Andrew Harrison, Alaska Airlines executive vice president and chief revenue officer. "These comfortable and highly efficient jets will expand and strengthen our already leading Pacific Northwest network."