Established by Congress during the late 1960's as a response to the growing number of airborne smugglers bringing drugs into the United States, the Air Program became operational in 1971. Using a variety of military surplus reconnaissance planes and helicopters, its mission was to reduce the flow of illicit drug coming in through the air and to assist other agencies with their interdiction efforts. As the problem became more acute, Congress authorized additional funding. The Air Program was able to add more assets and to begin experimenting with different technologies and tactics. As interdiction efforts became better and more extensive, the character of smuggling activities changed. Smugglers stopped landing in U.S. territory to offload their cargo, preferring instead to airdrop it to boats waiting offshore. As the surveillance and detection network has grown, the drop zones have moved farther and farther offshore. During this period of deterrence effectiveness, the Air Program is focusing on its second operational priority: assisting other agencies in aerial surveillance missions, including the tracking of trucks from the border to their destinations and coordinating interdiction missions with drug enforcement forces from neighboring countries. For the foreseeable future, the Customs Air Program will keep busy with support, training, and response to intrusions as needed.