"Traditionally aircraft have been the naval warfare hunters, and submarines have been the hunted. But as antiaircraft missile technology improves, it will become increasingly possible for nations to deploy such systems on submarines. Some submarines have a limited surface-to-air missile (SAM) capability that consists of employing small man-portable missiles for self-defense in tight situations. The evolution of SAM technology will enable several nations to develop feasible sub-based SAM systems. In addition to interdiction of sea lines of communication (LOCs), submarines could take on the new mission of interdicting air lines of communication (ALOCs) by attacking aircraft, a mission that would be strategically advantageous to certain nations. The primary targets of these antiaircraft attacks would be strategic high-altitude aircraft - theatre airlift, passenger planes, airborne warning and control system aircraft, and airborne tankers - that make relatively easy targets in terms of detection and interception by missiles."