The answer
Birds have physical wings with which to fly in the air, but human beings were given the Holy Spirit to fly up as though to heaven. St. Macarius the Great says, “When God created Adam, He did not provide him with bodily wings, like the birds, but He had designed for him the wings of the Holy Spirit, those wings which He purposes to give him at the resurrection, to lift him up and catch him away wherever the Spirit pleases which holy souls even now are privileged to have, and fly up in mind to the heavenly frame of thought. For Christians have a different world of their own, another table, other raiment, another sort of enjoyment, other fellowship, another frame of mind … The power of these things it is their privilege to have now within them in their souls, through the Holy Spirit; therefore at the resurrection their bodies also will be permitted to share those eternal blessings of the Spirit, and will be mixed with that glory, which their souls in this life had known by experience.”898
Fr. Tadros Yacoub Malaty
Notes
898 St. Macarius the Great, Fifty Spiritual Homilies of St. Macarius the Egyptian, trans., A. J. Mason (London: Society for Promoting Christian Knowledge, 1921) Homily 5.11: p. 54, amended.