Monthly variations of radiative forcing (RF) and mean temperature changes by greenhouse gases emitted from commercial aircraft were estimated based on the simplified expression at four international airports (Incheon, Gimpo, Jeju, and Gimhae Airports) during the years of 2009~2010. The highest RF and mean temperature change in the study area occurred at Incheon Airport, whereas the lowest RF and mean temperature change at Gimhae Airport. During 2009~2010, the mean RF and mean temperature change estimated from aircraft $CO_2$ emissions at Incheon Airport were approximately 30.0 $mW/m^2$ and $0.022^{circ}K$, respectively. The mean RF and mean temperature changes caused by other greenhouse gas $N_2O$ was significantly small (<<0.1 $mW/m^2$ and << $1{ imes}10^{-3}^{circ}K$). Meanwhile, $CH_4$ emissions caused negative mean RF ($-4.45{ imes}10^{-3}mW/m^2$ at Incheon Airport) and the decrease of mean temperature ($-3.83{ imes}10^{-6}^{circ}K$) due to consumption of atmospheric $CH_4$ in the aircraft engine.