Chicago ? Boeing Co. Chairman and Chief Executive Jim McNerney assured shareholders Monday that the company is in strong shape to ride out the “once-in-a-lifetime” downturn that has walloped its profits, jetliner orders and stock price.

Putting an upbeat spin on a slump that has hit both the aerospace company and its customers hard, he cited reasons for optimism: Boeing’s huge backlog of orders, diversification between commercial airplanes and defense and its continued, albeit halting, progress on the 787.