As fearsome as portable surface to air missiles (SAMs) are, they are not the most dangerous weapon for low flying aircraft. You can protect yourself against these small missiles with flares and warning devices. But small caliber (20-57mm) anti-aircraft guns are another matter. While not portable like the small SAMs, the enemy can set them up anywhere and basically ambush low flying warplanes or helicopters. Theres no way to divert the shells from these automatic weapons. Most modern warplanes and helicopters can take a few hits, but even one 20mm shell will hurt you enough to abort your mission, and a few of them in the wrong places can bring you down. Many of these small guns dont use any radar, so anti-radar missiles arent much good. Bombing them will work, once you find them. But the gun crews know that and will move often. Its a case of low tech still having an advantage.