There is no need to doubt the literal nature of Christ’s ascension, so long as we realize its purpose. It was not necessary as a mode of departure, for ‘going to the Father’ did not involve a journey in space and presumably he could simply have vanished as on previous occasions. The reason he ascended before their eyes was rather to show them that this departure was final.  He had now gone for good, or at least until his coming in glory.  So they returned to Jerusalem with great joy and waited – not for Jesus to make another resurrection appearance, but for the Holy Spirit to come in power, as had been promised.

—Understanding the Bible, 103.

It is a pity that we call it ‘Ascension Day’, for the Bible speaks more of Christ’s exaltation than of his ascension. This is an interesting avenue to explore. The four great events in the saving career of Jesus are described in the Bible both actively and passively, as deeds done both by Jesus and to Jesus. Thus, we are told with reference to his birth both that he came and that he was sent; with reference to his death both that he gave himself and that he was offered; with reference to his resurrection both that he rose and that he was raised; with reference to his ascension both that he ascended and that he was exalted. If we look more closely, we shall find that in the first two cases, the active phrase is commoner: he came and died, as a deliberate, self-determined choice. But in the last two cases, the passive phrase is more common: he was raised from the tomb and he was exalted to the throne. It was the Father’s act.

—The Exaltation of Jesus (sermon on Phil. 2:9-11)