8月4日电，波音防务工会拒绝签订为期四年的合同，准备发起罢工。

Core Viewpoint - Boeing's defense union has rejected a four-year contract and is preparing to initiate a strike [1] Group 1 - The union's decision indicates significant dissatisfaction with the proposed contract terms [1] - A potential strike could disrupt Boeing's defense operations and impact production schedules [1] - The rejection of the contract suggests ongoing labor tensions within the aerospace industry [1]