"O Mother of God,
today you are carried into heaven
on the chariots of the Cherubim,
the Seraphim wait upon thee
and the ranks of heavenly army
bow before thee."
(Armenian Liturgy: Feast of the Assumption)
To understand why Mary is Queen of the Angels we must see Christ's Redemption of the world within its Cosmic Perspectives.
Eve revolted against God at the instigation of the Evil One who told her that disobedience to God would not bring death but that they would become gods "knowing what is good and what is evil". (Gn 3:5) So now it is through the ministry of the Angel Gabriel that Mary consents to become the Mother of the Messiah.
Christ came to save mankind from the power of evil, those cosmic powers which brought about the dynamics of death in the world. At Capernaum an evil spirit cried out to Jesus, "What have you to do with us, Jesus of Nazareth? Have you come to destroy us? I know you are the Holy One of God." (Mk 1:24)
Mary, conceived without Original Sin, escapes the power of the Evil One and becomes an ally with the good angel's struggle against the evil spirits. Further, Gabriel calls her "full of grace", a privilege which no angel had. St. Thomas Aquinas states that the angels having beatific knowledge see in the Word the mysteries of faith. (Summa Theologica, Q. 57, Art.5) So the angels rejoiced at Christ's birth and understood the profound significance of this event. They would have to adore Christ as the God-man and honor his Mother because she was God's beloved, magnificent in holiness and resplendent in her glory.
The crown Mary received is one of justice, powers and glory. Now she exercises real power, after Christ, toward the angels. The Angel Gabriel, Michael and Raphael as leaders of the heavenly hosts are ever ready with joy to carry out the commands of the Mother of God and Queen of Heaven.
Hail Holy Queen: Midi Sequence by Bob Sorem
Hail, holy Queen enthroned above; O Maria!
Hail, mother of mercy and of love. O Maria!
Triumph, all ye cherubim; sing with us, ye seraphim!
Heav'n and earth resound the hymn:
Salve, salve, salve, Regina!
Crowning of Mary