Union strikes may become a protracted battle, Boeing Company's financial difficulties are feared to worsen further.

The union leader of Boeing Company (BA.US), Jon Holden, said in an interview on Saturday that the strike "could last for a while" as workers believe they can get higher wages and better pension benefits. International Association of Machinists and Aerospace Workers (IAM) more than 30,000 members started the strike last Friday after overwhelmingly voting down a new contract. IAM produces Boeing Company's best-selling 737 MAX and other jetliners in Seattle and Portland. Boeing Company and union negotiators will return to the bargaining table this week for negotiations supervised by a federal mediator, after over 94% of workers rejected an initial contract proposal supported by Holden. Holden said that his members prioritize higher wage increases and restoration of the fixed pension plan, which IAM lost in the last round of negotiations with Boeing Company ten years ago. Holden said in the interview: "We have the most leverage and the most power at the most appropriate time in our history. Our members want us to utilize it." "I know our members are confident. They stand shoulder to shoulder, ready. So the strike could last for a while." The initial agreement included a 25% salary increase over four years and a commitment to build the next commercial plane in the Seattle area if the aircraft project is launched within the contract's four years. Union members expressed dissatisfaction with years of stagnant wages and rising living costs, stating that Boeing Company's proposal to eliminate performance bonuses would reduce overall wage growth by half. Boeing Company's stock fell 3.7% last Friday. The stock has fallen by nearly 40% this year, with a market value loss of about $58 billion. An extended strike could further damage Boeing Company's financial condition, as the company is already struggling with $60 billion in debt. A prolonged halt in aircraft production would also put pressure on airlines that operate Boeing Company aircraft and manufacturers of aircraft components.