Boeing Hardens Tone With Union, Laments ‘Bad Faith Bargaining’

With the paralyzing labor strike now running for a full four weeks, Boeing Co. is taking a harder line with union representatives by filing unfair labor practice charges, saying the other side has bargained in bad faith and undermined its own deal.

The US planemaker said it decided to “reluctantly” to file the charges in response to the International Association of Machinists and Aerospace Workers leadership’s own legal filings, seeking to provide an “an accurate picture of the events of the past few weeks,” according to a statement late Thursday. The union has said it’s willing to talk, though Boeing ...