Ho Chi Minh trail
There is little place for air interdiction in fighting a local insurgency, in the most common sense of interrupting lines of supply. Only when the insurgents are being supplied from across a border, or at least from a remote area of sanctuary in the country, does this make sense. In the case, for example, of the Ho Chi Minh trail, any useful level of interdiction required either high-risk direct observation by special reconnaissance troops, or, in some cases, airborne sensors, such as the Vietnam-Era "Black Crow", which detected the "static" produced by the ignition system of trucks on the Ho Chi Minh trail, from distances up to 10 miles.