The U.S. Navy/Marine Corps Class A flight/flight-related mishap rate has declined markedly since 1953. However, analysis of all Class A, B, and C naval aviation mishaps between January 1977 and December 1992 reveals that mishaps attributable to human factors have declined at a slower rate than those attributable to mechanical/environmental factors. Upon closer inspection of the data, marked differences were evident between single-piloted and dual-piloted aircraft. Global trends were primarily a function of single-piloted aircraft, particularly when phase of flight and time of day that a mishap occurred are considered. Previously reported improvement in aviation safety may be biased by global assessments that do not differentiate among mishap causal factors and single- versus dual-piloted aircraft.