I am quite sure a number of GA
airports have been flooded in whole or part too. Some GA
airports are located in river valleys or flat plains near rivers subject to flooding like that occuring now in Northern NJ
and Various location along the Deleware River (PA, NJ
, NY State). Development in many places has changed water flows, less land to absorb heavy rains and more drainage due to paving from development. In most cases as to Major airports, you do have the potential problems of flooding due to being located near coastal areas (many) or significant rivers. Many airports in the Carrbbean, and along the Gulf of Mexico and Eastern USA by the Atlantic Ocean, could be subject to flooding from coastal storms, tropical storms and Hurricanes in season (as noted in an above picture). I would suspect that all airport locations try to avoid the potential of flooding but not all cases can be avoided.