March 3, 2007: The U.S. Air Force has about 14 percent of its 5,800 aircraft grounded, or under flight restrictions, because of age. A combination of post-Cold War cutbacks, and increased operations in support of the war on terror, have prematurely aged, an already elderly air fleet.

With the end of the Cold War, air forces around the world stopped buying new aircraft, and many thousands of fighters and bombers were put into storage or scrapped. With the threat of World War III gone, or at least greatly diminished, most nations were quite happy to cut back on buying and using expensive, high performance warplanes. The air force generals were not happy, but they had no leverage over the people who controlled the money. That's been changing. After more than a decade of miniscule new aircraft purchases, the aging air fleets are beginning to show their age in unpleasant ways.

But it's a little more complicated than that. First, many air forces have been able to replace elderly aircraft by purchasing used aircraft from countries that retired many little used warplanes, as they reduced the size of their air forces. Both the United States and Russia had hundreds of late model warplanes on the second-hand market. Second, with no war on the horizon, air forces could cut back on the number of hours their pilots spent in the air, training for combat. This made aircraft last longer, as their useful lives were measured in hours in the air. Third, air warfare went through some fundamental changes in the 1990s. Smart bombs got a lot smarter and cheaper. This meant fewer aircraft could destroy more targets, and fewer aircraft were exposed to enemy fire, or the wear and tear of just being up there. Less wear and tear, and battle damage, means older aircraft can serve even longer.

But some aircraft, mainly tankers and transports, were still being heavily used. And it's these combat support aircraft that are most often grounded or restricted. And this brings us to our final problem. It's easier to get money to buy warplanes, especially jet fighters, than it is to purchase tankers and transports. Fighters are, well, sexier, and thus easier for air force generals to ask for. But what is really needed are replacements for aging tankers and transports. The result in hard time for those running an air force.