If the US Airways flight that yesterday took off from La Guardia and got only as far as the Hudson River suffered the "double bird strike" claimed by its pilot, it would just be the latest incidence of a two-pound creature downing a 91,000-pound plane. The Bird Strike Committee USA (yes, such a body exists) claims that bird-to-plane collisions cost the civil and military aviation industries $600 million annually and have resulted in 219 fatalities in the past 20 years.Some "fun" facts from the B