'Air' in the Bible

“The sower went out to sow his seed; and as he sowed, some fell beside the road, and it was trampled under foot and the birds of the air ate it up.

And Jesus said to him, “The foxes have holes and the birds of the air have nests, but the Son of Man has nowhere to lay His head.”

It is like a mustard seed, which a man took and threw into his own garden; and it grew and became a tree, and the birds of the air nested in its branches.”