Grounding the air force

Our military is the last bastion of defense for this country. However, it seems as though the military in general and the Air Force in particular are being left to whither away on the vine, a fact noted in this Associated Press article: http://news.aol.com/story/_a/military-warns-of-geriatric-air-force/20080219094809990001?ncid=NWS00010000000001. Forty year old planes? How can we expect the supposedly most advanced military in the world to defend this country with equipment that is literally as old as I am? That's not adequate to defend against existing threats, let alone the ones that will emerge in the future.