Southwest Airlines Scare Highlights Aging of US Fleet

As the Federal Aviation Administration starts checking Boeing 737s for cracks after Friday's near disaster with a Southwest Airlines jet, there are looming questions about the age of US airplanes.

Forty-four percent of the US fleet of passenger planes is at or near retirement age, 22 years of service. The average age of all U.S. airplanes right now is 12 years.

Troy Lahr, an aerospace and defense analyst with Stifel Nicolaus, told CNBC Tuesday:"If you look at the U.S. domestic airlines they largely have been underspending on their aircraft fleets for a decade. There is a big upgrade cycle that will be coming over the next few years as airlines replace their older models."

Most U.S. based airlines would prefer Boeing to any foreign competitor, including Europe's Airbus and Brazil's Embraer, analysts say.

While there are backlogs at Boeing for the long-haul airplanes like the 787, Boeing is churning out shorter-haul planes like the 737s—often used for domestic flights—much more rapidly. The rate on new 737s is about one every eleven days.

Lahr has had a buy rating on Boeing for two years and a price-target of $90 a share. He believes peak earnings won't come in until 2015 or 2016.

"Once you start seeing some domestic airlines start to place orders investors will realize there is reason for optimism," he says

Delta and United have already started talking about replacing many of their narrow body aircraft, and orders are expected within the next 18 months.