The U.S. F-16 is the most numerous post-Cold War jet fighter, with over 4,200 built, and more to come. During The Cold War, Russia built over 10,000 MiG-21s, and the U.S over 5,000 F-4s. The F-16 can also function as a bomber and ground attack aircraft, although not as effectively as the air force folks would have you believe. It can carry four tons of bombs. In air-to-air combat, it has shot down 69 aircraft so far, without losing anything to enemy warplanes. It was originally designed as a cheaper alternative to the heavier F-15.
The F-16 are sturdy, and one has spent 7,000 hours in the air before being retired. The F-16C was originally designed for a service life of 4,000 hours in the air. But advances in engineering, materials and maintenance techniques have extended that to over 8,000 hours. The F-16 is used by 25 different countries. The aircraft is still in production, and is to be replaced in U.S. service by the F-35. But with delays in getting F-35 production going, and trouble keeping the F-35 price down, it appears that the F-16 will remain in production for another decade. Part of the reason for that is the adaptability of the F-16. It's one of those aircraft that is easily upgraded.
Consider the Israeli F-16I. This is a 24 ton, two seat fighter-bomber, and is probably the most capable F-16 model in service. It's basically a modified version of the F-16C/D Block 50/52, equipped with a more advanced radar (the APG-68(X)) and the ability to carry Israeli weapons like the Python 4 air-to-air missile and the Popeye 2 air-to-surface missile. Costing $45 million each, the F-16I has an excellent navigation system, which allows it to fly on the deck (a few hundred feet from the ground), without working the pilot to death. The aircraft can do this at night or in any weather. The F-16I can carry enough fuel to hit targets 1,600 kilometers away (meaning Iran is within range). The aircraft uses the latest short and long range air-to-air missiles, as well as smart bombs. Electronic countermeasures are carried, as is a powerful computer system, which records the details of each sortie in great detail. This is a big help for training. The F-16I is basically optimized to deliver smart bombs anywhere, despite dense air defenses. This further increases Israels military power versus its neighbors. Israel has received 102 new F-16I fighter-bombers in the last five years. Added to this will be another 125, as older F-16s are upgraded.
What is more likely to put the F-16 out of business are unmanned aircraft like the MQ-9 Reaper. The 4.7 ton Reaper has a wingspan of 66 feet and a payload of 1.5 tons. Reaper is considered a combat aircraft, because it can carry everything from the hundred pound Hellfire missile, to the 500 pound laser or GPS guided smart bomb. Reaper has a laser designator, as well as day and night (infrared) cameras. Reaper can stay in the air for over 14 hours and operate at up to 50,000 feet. A fully tricked out Reaper costs about $18 million per aircraft (with all the high end sensors).
Thus the 19 ton F-16 costs more than twice as much as a Reaper, and is much more expensive to operate. The F-16 uses over a hundred times more fuel, per hour in the air, and with the price of oil rapidly rising, that itself means a lot. Put simply, It's cheaper, more effective, and safer (for pilots) to use Reapers (or similar aircraft) for a lot of the ground support work. Fighters are still needed to keep the skies clear of enemy aircraft, although Reapers are better suited for the dangerous work of destroying enemy air defenses. But for fighting irregulars, the Reaper is king, and there are more bad guys with guns on the ground, than in the air.