In the last few decades, American jet fighters have evolved away from the classic aerial dog fight (either with short range heat-seeking missiles or cannon), and towards BVR (Beyond Visual Range) battles utilizing long range radar and missiles that can think for themselves. It's just as well, because two potential foes may resort to an old World War II tactic; suicidal use of their aircraft to ram American bombers or fighters.
The most widely known suicide pilots are the World War II Japanese Kamikaze, but the Germans and Russians also organized ramming squadrons, to take down enemy bombers. Iran and North Korea are inclined towards this kind of tactic as well.
The Japanese developed the idea of sending suicide aircraft against American ships, mainly because they had no other way of making a dent in the U.S. fleet. In the Summer of 1944 the Japanese formed "Special Attack Units." Plenty of pilots volunteered to fly their bomb laden aircraft right into American ships. In effect, the Japanese had invented the cruise missile, for that's how the Japanese suicide bombers operated. Come in low, under the radar, and head right for enemy warships. In some ways, the Kamikaze were superior to modern cruise missiles, as the Kamikaze pilots could take evasive action against anti-aircraft fire and enemy fighters, and were not fooled by electronic warfare or deceptions. In the last three months of 1944, the U.S. fleet off the Philippines was attacked by 378 Kamikaze bombers (escorted by several hundred fighters, of which 102 were lost). All the Kamikaze were shot down, or hit an American ship. The U.S. losses were heavy, with 16 ships sunk (two escort carriers, three destroyers, one mine layer, plus ten smaller vessels) and another 87 damaged (including 21 carriers, five battleships, ten cruisers, 23 destroyers and six smaller warships). Thousands of sailors were killed or injured. The next big use of Kamikaze was March-June 1945, during the Okinawa Campaign. The Japanese had 1,900 aircraft attacking 587 ships, of which 320 were warships. Each attack averaged 150 aircraft. One had as many as 350 warplanes. Vigorous defensive measures shot down 93 percent of the Kamikazes. Even so, eighteen percent of the ships hit were sunk or put out of action.
In 1945, as American B-29 bombers blasted Japanese cities to cinders, the Japanese turned their Kamikaze against the American four-engine bombers. It's unknown how many of the 360 B-29s lost over Japan were due to the Kamikaze. It's believed less than ten percent of the bombers were lost to ramming, and many of those were carried out by regular pilots (some of whom parachuted from their fighter before it hit the bomber, and lived to report the incident), not Kamikaze
Less well known is the ramming tactics adopted by the Russian Air Force against the Germans, and the German Air Force against American daylight bombing raids during World War II. The Russians recorded 636 ramming attacks during the war (1941-45), which destroyed about the same number of German aircraft. About two-thirds of the Russian pilots survived, either by bailing out, or landing their badly damaged aircraft.
The Germans first considered ramming in early 1943, and began using such tactics by late 1943. These attacks continued, intermittently, until the end of the war. Less than a hundred American bombers were destroyed by these tactics, and about the same number of German fighters were lost. Specially armored and heavily armed fighters were used for these attacks, which were not supposed to be suicidal, just very dangerous. Most "Rammjaeger" pilots did manage to bail out, but it was difficult to equip the special Rammjaeger aircraft, and the tactic never became a serious threat to the American bombing effort.
But against hundred million dollar American fighter, warships or key ground facilities, that formula may change in a future war with Iran or North Korea. Iran and North Korea both already encourage suicidal attacks, and all you have to do is organize this sort of thing to produce something really scary.