The U.S. Air Force has decided to buy several hundred of the vertical takeoff version of the F-35 warplane (the F-35B). Originally, the air force was planning to buy about 1,600 of the standard F-35A, which take off normally, from an airfield, and no F-35Bs. The F-35A version is to cost about $32 million each, while the vertical takeoff (F-35B) version costs about 25 percent more. The decision to get the vertical takeoff F-35B can be attributed to changes in the way air power is being used. Persistence (having warplanes over the combat zone 24/7) is seen as the key to winning future battles. Having F-35s spend hours flying in from distant bases makes it difficult to maintain that 24/7 coverage. But having vertical take off F-35Bs sharing helicopter bases close to the front line is another matter. Air fields take time to build and lots of effort to defend and maintain. The air force has seen how the marines vertical take off AV-8 Harrierss have operated for two decades, and know vertical take off combat aircraft can work this way. The 25 ton F-35Bs can be on call, and able to get to a hot spot in minutes, with up to six tons of bombs and missiles. F-35B forward bases would sometimes have a rough air field, so that C-130s could fly in with bombs, spare parts, and some fuel. This is cheaper than using helicopters for resupply. Most of the needed fuel could be delivered in the air, via aerial tankers. The tankers can keep the F-35s in the air as long as they are needed. But a major selling point for the F-35B is its ability set down just about anywhere when there is no current need for a bomber up there. And if the F-35Bs are close enough to the fighting, they can be up and over the battlefield in 10-15 minutes. This saves fuel, and wear and tear on the aircraft. 

Because of the higher cost of the F-35B, compared to the basic F-35A, the air force may end up ordering fewer F-35s. Congress is vexed at the high cost of new air force aircraft, and has not shown any interest in paying more.