Increasing concerns over Boeing's cash flow generation pushed analysts to downgrade expectations for the stock.Wells Fargo analyst Matthew Akers shocked the market this week when he dropped his price target on Boeing (BA -1.73%) to $119 (down from$185) and cut his rating to underweight from equalweight. The new target represents a 26% discount to the current price.Should investors take Akers' update as valid and consider selling the stock? Boeing gets a downgradeAn analysis of Akers' report suggests his re ...