A system operates to guide an aircraft to or along a route designed to maintain the aircraft within a safe glide distance of an acceptable —radar or radio coverage—area. The system uses a database of —radar or radio coverage—areas with glide characteristics of an aircraft to determine a route that minimizes travel time or other specified parameter, while keeping the aircraft within a safe glide distance of a —radar or radio coverage—area in the database meeting the —radar or radio coverage—requirements for the aircraft.