And God said,
Let the waters bring forth abundantly the moving creature that has life, and fowl that may fly above the earth in the open firmament of heaven.
All Commentaries on Genesis 1:20 Go To Genesis 1
Basil the Great
God also said, “Let birds fly above the earth across the firmament of the heavens.” Why did he give winged creatures also their origin from the waters? Because the flying animals have a certain relationship, as it were, with those that swim. For just as the fish cut the water, going forward with the motion of their fins and guiding their turns and forward movements by the change of their tails, so also in the case of birds, they can be seen cutting and moving through air on wings in the same manner.