Objection 1. It would seem that Christ's body did not ascend above every spiritual creature. For no fitting comparison can be made between things which have no common ratio. But place is not predicated in the same ratio of bodies and of spiritual creatures, as is evident from what was said in I, 8, 2, ad 1,2 and I, 52, 1. Therefore it seems that Christ's body cannot be said to have ascended above every spiritual creature.
Objection 2. Further, Augustine says (De Vera Relig. lv) that a spirit always takes precedence over a body. But the higher place is due to the higher things. Therefore it does not seem that Christ ascended above every spiritual creature.
Objection 3. Further, in every place a body exists, since there is no such thing as a vacuum in nature. Therefore if no body obtains a higher place than a spirit in the order of natural bodies, then there will be no place above every spiritual creature. Consequently, Christ's body could not ascend above every spiritual creature.
On the contrary, It is written (Ephesians 1:21): "God set Him above all principality, and Power, and every name that is named, not only in this world, but also in that which is to come."
I answer that, The more exalted place is due to the nobler subject, whether it be a place according to bodily contact, as regards bodies, or whether it be by way of spiritual contact, as regards spiritual substances; thus a heavenly place which is the highest of places is becomingly due to spiritual substances, since they are highest in the order of substances. But although Christ's body is beneath spiritual substances, if we weigh the conditions of its corporeal nature, nevertheless it surpasses all spiritual substances in dignity, when we call to mind its dignity of union whereby it is united personally with God. Consequently, owing to this very fittingness, a higher place is due to it above every spiritual creature. Hence Gregory says in a Homily on the Ascension (xxix in Evang.) that "He who had made all things, was by His own power raised up above all things."
Reply to Objection 1. Although a place is differently attributed to corporeal and spiritual substances, still in either case this remains in common, that the higher place is assigned to the worthier.
Reply to Objection 2. This argument holds good of Christ's body according to the conditions of its corporeal nature, but not according to its formality of union.
Reply to Objection 3. This comparison may be considered either on the part of the places; and thus there is no place so high as to exceed the dignity of a spiritual substance: in this sense the objection runs. Or it may be considered on the part of the dignity of the things to which a place is attributed: and in this way it is due to the body of Christ to be above spiritual creatures.
Source: Summa Theologica (New Advent)