Warplanes are expensive, not just to build, but also because of the tremendous research and development costs. Some current examples are; B-2 bombers which cost $2.1 billion each, C-17 transports are $329 million, C-130J transports are $117 million, V-22 tilt rotor transports are $110 million, F-35 fighters are $104 million, E-18 jammer aircraft are $96 million, F-18 naval fighters are $95 million, MH-60R special operations helicopters are $44 million, while the MH-60S model is $29 million each.
It is often pointed out that the construction cost alone is much lower. That's true, it costs less than $400 million to build one new B-2. But the R&D costs have to be paid, and a portion of that cost has to be applied to each of the aircraft built. Obviously, the more aircraft you build, the lower the R&D cost per aircraft. While R&D work continues over the life of the aircraft type, most of it occurs before mass production begins. However, a growing trend is to make substantial improvement in aircraft over the two or more decades they are in service. This results in substantial R&D costs, which, makes new aircraft even more expensive.
The more expensive aircraft are also much more capable, durable and easier to maintain and repair. There capabilities are further increased by more capable (and more expensive) weapons. For example, the JDAM bomb kit (added to 500, 1,000 and 2,000 pound bombs), cost $26,000 each. The longer range JSOW (JDAM with wings and more powerful guidance system), cost $460,000 each. The even longer range JASSM cost $930,000 each. But perhaps the most anticipated smart bomb is the SDB (Small Diameter Bomb), a 250 pound JDAM that can also punch through concrete bunkers and other structures. These cost $60,000 each.
Since the introduction of the JDAM bombs, the ground troops are not nearly as critical of the high cost of warplanes. The grunts now see themselves getting a lot more benefit from those gold plated flying machines, because the smart bombs are clever enough to hit targets exactly where the soldiers or marines want them hit.