The United States, with 13,200 planes, has the largest fleet of military aircraft in the world. That’s a quarter of 53,500 aircraft total for the entire world. The second largest fleet, 4,100 aircraft, belongs to Russia while number three is China with 3,200 aircraft. In terms of balance-of-power and who has what in potential conflicts, China comes off poorly. Having made enemies of South Korea, Japan and Taiwan, China finds these three nations have combined air forces slightly larger that China's. Add in several thousand American aircraft that can be brought in quickly and China is at a considerable disadvantage. Russia is an ally but its warplanes are largely elderly and many are close to retirement. In addition, Russia is the largest country in the world and many neighbors are actually or potentially hostile. The existing Russian air forces are needed in many other areas besides the Pacific Coast.
In terms of numbers, the United States and its allies have an overwhelming advantage as well as an edge when it comes to technology. All this comes at a cost, one the United States is having a particularly difficult time dealing with. It is even worse in Russia, where forced retirements. from old age or lack of money for maintenance, will soon see Russia slipping into third place.
The aging American warplane fleet will not shrink as rapidly and China has not been growing as fast as it could because a lot of inexpensive Cold War era aircraft are being replaced with much more expensive modern models. China does see that situation changing in their favor during the next two decades.
Currently the U.S. has more military aircraft because it has enormous shares of the world supply of support aircraft. America has 19 percent of fighters and bombers but 38 percent of all Special Mission (transport and reconnaissance) aircraft and 76 percent of aerial tankers. This enables the U.S. to move combat aircraft to any part of the world quickly and ready to go to work. No other nation has that capability. Other nations can move a small number of warplanes long distances but none have the need, or the budget, to do more. The American global reach is a major asset for allies worldwide and they are concerned about the gradual decline of that global reach. Without the Americans, many current U.S. allies would have to buy the support aircraft they need.
The most numerous American combat aircraft is the F-16, whose average is 29 years. The F-15s average 35 years. Worldwide these two aircraft accounts for 22 percent fighter aircraft used by all nations. Add in the U.S. Navy F-18 and these three are 28 percent of all fighters worldwide. There are 4,000 of these three models and the U.S. hopes to replace them with nearly as many F-35 stealth fighters. That effort is well underway with about 500 delivered so far. The question is, can the military budgets of the U.S. and export customers keep it up?
Two other issues remain unresolved. One is the age of combat aircraft. The F-35 was late arriving in large numbers and the F-16s and F-15s they were to replace are still in service. As aircraft age, maintenance costs rise and the air force budget is not rising to deal with that. As a result, readiness rates for these older aircraft have been falling during the last few years. At the same time, most of the aircraft have benefitted from tech upgrades. Not just new electronics but also components made of new materials. Despite all that, age and increasing maintenance costs eventually prevail in the form of lower readiness rates. However, with enough money and motivation, the older aircraft can still maintain high readiness rates. Sometimes that additional cost is found to be cheaper than developing and building a new aircraft.