Many pilots fly ten percent, or more, of their training missions on simulators. That is, pilots in nations that can afford to let their pilots train. With the increasing cost of fuel, and weapons, simulators are becoming a more attractive way to create skilled pilots, and maintain those skills. Moreover, the cost of simulators is coming down, particularly those that dont try to replicate everything. Many flying functions can be practiced with simpler simulators, which basically PCs and some large video displays.
Pilots have always been a bit wary of simulators, even though the devices have been in use for over 70 years and have a record of success. Thus it takes a combination of actual, and simulator missions, doing the same thing, to keep it real, and the pilots confident about the simulators. The air force is also touchy about who is building the simulators. When the U.S. Army recently approached the air force about using army simulators to train soldiers to be FACs (Forward Air Controllers), the air force turned them down. The air force wants lots of practice with actual aircraft when training FACs, and was not too confident in the ability of the army to create an acceptable simulator for FACs.
The growing popularity of UAVs, and the need for trained operators, has led to flight simulators for UAVs. These are a lot cheaper to build, because UAV operators dont get much in the way of graphics beyond what they can see on a computer screen.
Another inexpensive feature has been networking. This is the ability of two or more flight simulators to operate together via the Internet or a similar connection. This allows pilots to fly together, fight each other and generally increase the training experience.
Increasingly, the most interesting flying that combat pilots are doing is not in their aircraft, but in simulators. When smart bombs and missiles are involved, the cost of one training sortie can easily exceed $100,000 per aircraft. Thus more of that kind of training is being done using highly realistic (and expensive) simulators. Using vivid graphics, projected on domes around the cockpit, much of the expense for these simulators goes into the software, that makes them nearly a hundred percent compatible with the actual aircraft. This degree of realism is necessary, otherwise you are teaching the pilot how to do things that dont quite work that way in real life. As a result, these high end simulators sometimes cost as much as the actual aircraft. But unlike the aircraft, the simulators can be run around the clock, at a cost of a few hundred dollars per sortie. These highly realistic simulators are also used for helicopter pilots, especially those flying the souped up choppers used for commando operations.