Ratings on Chicago, Ill.-based Boeing Co. are supported by its position as one of two global producers of large commercial aircraft, generally favorable long-term fundamentals for that business, a very strong position in defense and military space with moderately attractive growth prospects, efficient operations, and expected good overall financial performance. The ratings also acknowledge currently weak demand for commercial airplanes and sizable unfunded postretirement liabilities. The Sept. 11, 2001, attacks, a sluggish global economy, the lingering effects of the Iraq war, and the outbreak of severe acute respiratory syndrome (SARS) have had a severe impact on commercial aviation, leading to a decline in air travel, excess capacity, and deep losses by many airlines, especially those in the U.S. As a