|Effect||Each air unit built here starts life hardened. Air units here at the end of a turn will have their health doubled.|
|Required technology||Advanced Flight|
An airport will be built fairly late in the average C-evo game.
Those built near the frontier will be primarily for quick air unit repair.
Those in larger, more central cities are more likely to be used for building air units; if Line Production is in effect, a particular air unit is likely to be built in only one or two airport cities because of the cost of the first one in a line.