Final answer:
Military Training Routes (MTRs) are used by military aircraft for low-altitude training and are typically established below 10,000 feet MSL to separate them from commercial airspace, which is strictly regulated by the FAA for safety.
Step-by-step explanation:
Military Training Routes (MTRs) are designated pathways in the sky for military aircraft to conduct low-altitude, high-speed training exercises to maintain proficiency in tactical flying. These MTRs are typically established below 10,000 feet Mean Sea Level (MSL), ensuring that they are separate from the altitudes typically used by commercial airliners, which are regulated to have specific spacing to avoid collisions. The Federal Aviation Administration (FAA) sets strict rules where commercial aircraft must maintain a distance of five miles laterally from others at the same altitude, and either 2,000 feet or 1,000 feet vertically, depending on their altitude. Such detailed air traffic regulations are essential for maintaining safety in both commercial and military aviation.