SEATTLE, Sept 14 (Reuters) - A strike at Boeing ( BA ) "could

go on for a while" as workers are confident they can get bigger

wage increases and an improved pension, union leader Jon Holden

said in an interview with National Public Radio on Saturday.

More than 30,000 members of the International Association of

Machinists and Aerospace Workers (IAM), who produce Boeing's ( BA )

top-selling 737 MAX and other jets in the Seattle and Portland,

began a strike on Friday after overwhelmingly voting down a new

contract.