Bernstein cuts Boeing's PT over cash flow concerns, delivery delays

** Bernstein cuts Boeing's BA PT citing cash flow concerns, delivery delays and issues from co's defense unit

** Brokerage cuts BA's PT by $15 to $207, Rates "Outperform"

** Bernstein says lack of internal knowledge, personal networks might be challenging for co's new CEO Kelly Ortberg

** Brokerage says ramp on production is a tailwind but adds that "it will be important to see progress"

** Shares of BA down ~2% at $165 in premarket trade

** BA YTD down ~34%