He is conflating angels and angels as.... classically depicted.
He extrapolates from angels as classically depicted being unable to fly to cherubs and angels being unable to fly.
A rather big leap that he makes there.
ANGELS do not eat.
They have no need for a large intestine, a small intestine, an appendix, most of the other organs below the diaphragm, or, when you get right down to it, the liver!
This gives them considerable room for the installation of rockets ~ and since they've had billions of years (since the creation of the multiverse) to work things out, those rockets are remarkably efficient, compact, and virtually invisible to human beings.