SEATTLE (AP) -- Boeing Co. machinists voted overwhelmingly Wednesday for a preliminary strike authorization in a show of support for union negotiators in contract talks with the aerospace giant.

Around 15,000 members of the International Association of Machinists and Aerospace Workers District Lodge 751 showed up at KeyArena, with 99 percent voting in favor of the strike authorization, union spokeswoman Connie Kelliher said.

Union members in Wichita, Kan., and Portland, Ore., also approved strike authorization by similar margins, she said.

The vote is procedural and does not actually authorize a strike or indicate that one is likely.

The current contract expires Sept. 3. An additional vote by union members would be required before any walkout could occur.

About 18,400 machinists in the Seattle area, Wichita, and the Portland area struck for four weeks in 2005, forcing the company to halt production of commercial airplanes. The machinists assemble Boeing's commercial planes and some key components.

Union officials said the most important issues this time around include job security, general wage increases, a guaranteed pension plan and improving health care benefits.

"We're in the strongest position we've been in in 10 years, and we intend to leverage that unity," District 751 President Tom Wroblewski told the crowd.

"The fact is, by the time you've had your second coffee break on your first day, Boeing CEO Jim McNerney has already made more than you will all year," he said.

District 751 members haven't had a general wage increase since 2004, but have had lump sum bonuses and cost of living adjustments, according to Boeing spokesman Tim Healy.

Union members are still resentful over the past two contracts, in 2002 and 2005, Wroblewski said.

In 2002, the union accepted concessions due to the economic downturn after the Sept. 11, 2001, terrorist attacks. By 2005, machinists complained that the company had brought them a bad contract when it was doing well.

"It's payback time!" union official Mark Blondin told the crowd. Blondin was District 751 president in 2005 and now oversees all IAM contracts with Boeing.

Boeing's commercial airplane manufacturing operation, based in the Puget Sound area, has led a resurgence by the Chicago-based company in the past two years amid heavy orders for the much-awaited and increasingly delayed 787.

Healy noted that Boeing has been successful in recent years and said the company wants to share that success with its employees.

"We need a contract that rewards employees but allows us to continue having that success," he added.

The company thinks a new contract will be reached by Sept. 3, he said.

Contract talks started May 9.

The union currently represents about 25,000 Boeing employees in the Puget Sound area, around 1,800 in Wichita and 800 in the Portland area.

The average Boeing machinist has 17 years of experience and makes $27 an hour or about $56,000 a year. The pay scale ranges from $8.72 an hour to $35.13 an hour.

Robert Fowler, a seven-year Boeing veteran, wants better health benefits, stronger job security and a general wage increase.

"Typically if you look at the top 40 people at the Boeing Co. they make 1,000 times what machinists make, and we're the backbone of the company," he said.

Fowler doesn't want to strike, but will if he thinks it is necessary.

"This meeting is a sanction to use the baseball bat, and hopefully we won't have to but we need the ability to use it if necessary," he said.