The environment of world civil aviation in the 21st Century is expected drastic changes boty in terms of quantity and quality such as the introduction of hypersonic aircraft and large capacity aircraft with 500 to 1200 seats, introduction of CNS/ATM, construction of new large airports to accommodate the operation of new aircraft and sonic problems, and etc. Traffic forecast also shows its steady increase world wide but the growth rate in Asia Pacific region is more remarkable. Particularly North East region including Japan, China, Korea & Taiwan will play more important role, deregulation and privatization of airlines and airport will continue and extend to more areas. Alliances among airlines may be varied and enlarged. And so this may increases more fierce competition among major alliance networks. Challenging the 21st century of these changes, the paper reviews and discusses first, present status and major changes of world civil aviation, second present status of Korean civil aviation among 185 states of ICAO (Republic of Korea ranked 6th in terms of ton-kilometer carried by her two Flag carriers in 1997 and 1998), third, major issues and direction of Korean civil aviation policy in future, fourth, stategy and methods of civil aviation cooperation between North and South Korea. Finally, it summarizes, concludes and suggests how to challenge the 21st century in order to enhance and maintain the leading status of Korean civil aviation successfully.