Boyd’s Bible Dictionary:
(flying). The Hebrew original embraces birds in general (Gen. 1:20; 1 Kings 4:23). The Greek provides the domestic limitation (Luke 12:24).
Concise Bible Dictionary:
This term is used for every description of bird described as of the heaven and of the air, including those that feed on carrion, as in Genesis 15:11 and Revelation 19:17, 21; and those for the table (1 Kings 4:23; Neh. 5:18).