Market positions, as one of two global producers of commercial aircraft and a leading U.S. military contractor; Robust backlog and strong demand for commercial aircraft; Exceptional liquidity, with cash and short-term investments of $11.3 billion as of Dec. 31, 2011; and Substantial cash generation over the next two years, as deliveries of new and existing jetliners increase Challenges raising production rates on existing aircraft models and modifying and delivering 787s already built; Likely lower sales and earnings in the defense segment because of military budget cuts; and Significant underfunded pension and retiree health care obligations resulting in somewhat subpar credit protection measures The ratings on Chicago-based Boeing Co. reflect its position as one of two global producers of large commercial