Since the '91 Gulf War, the two worst incidents of U.S. Marine Corps friendly fire deaths, have been due to errors by U.S. Air Force personnel (one in Kuwait and one on the Horn of Africa). In fact, since World War II, more U.S. troops have been killed by U.S. Air Force bombs and bullets, than by enemy aircraft. But for the marines, this is not just bad luck and the result of battlefield confusion. The marines know there is a better way. Marine Air is unique: it specializes in ground support of fellow marines. The army should be so lucky. Marines fly F-18s that take care of most marine ground units close air support needs. The pilots of those F-18s are marines, and those pilots have served on the ground. This makes a big difference. The marine pilots are more successful in their attacks on ground targets, and kill fewer friendly troops in the process. The U.S. Army has to depend on U.S. Air Force aircraft, and the results are not as positive as for the marines.
Many countries have their armies operate like the marines, with the army owning and controlling the jets that specialize in ground support. Air force generals believe it's more important to save money by having the air force control everything that flies. Economies of scale and all that. But the troops on the ground die to make those economies of scale possible, and it's a problem that the senior generals, by mutual agreement (to not start a fight that will hurt everyone in the bureaucracy) avoid confronting.
The elimination of dumb bombs by GPS and laser guided bombs has greatly reduced the friendly fire incidents by air force warplanes. But the marines still prefer to have marines flying the ground support aircraft.