Next Big Future has an interesting article comparing purchase and operating costs of US Air Force and US Navy combat aircraft. Among its features was this graphic (click it for a larger view).
If you do a little basic arithmetic, you find that the cost of buying, say, an F-35 (as cited in the article) will be matched by its operating costs within less than half the aircraft’s expected service lifespan – less, if inflation drives up those operating costs (as it almost certainly will). Therefore, even after the aircraft have been bought, their ever higher operating costs will continue to eat up the defense budget for years to come.
I think the US Navy is taking a very intelligent look at the situation, with its recent decision to upgrade its older Super Hornet aircraft and buy new ones to add to its inventory. Their purchase price and operating costs are far lower than the latest F-35 models, but the aircraft are almost as capable across the entire spectrum of military operations. That fleet mix bodes well for future Navy budgets. However, the USAF has “bet the farm” on stealth, and demands an all-stealth combat fleet at much greater expense. Can it afford to pay for it? Can the country afford such a force? Is it worth its expense, in terms of operational effectiveness? Only time will tell.