Pressure to end the strike is growing on new CEO Kelly Ortberg. Since going on strike last month, Boeing factory workers have repeated one theme from their picket lines: They want their pensions back.Boeing froze its traditional pension plan as part of concessions that union members narrowly voted to make a decade ago in exchange for keeping production of the company’s airline planes in the Seattle area.Like other large employers, the aerospace giant argued back then that ballooning pension payments threatened Boeing’s long-term financial stability.