Four more references to “heaven” in Luke’s Gospel:

Luke 21:11 there will be great earthquakes, and in various places famines and plagues; and there will be dreadful portents and great signs from heaven.
Luke 21:26 People will faint from fear and foreboding of what is coming upon the world, for the powers of the heavens will be shaken.
Luke 22:43 [Then an angel from heaven appeared to him and gave him strength.
Luke 24:51 While he was blessing them, he withdrew from them and was carried up into heaven.

First, 21:11 indicates the source — “from” heaven — of dreadful portents. So, out of heaven — out of God’s presence and as a result of God’s judging decision — astral signs appear.
Second, 21:26 is more than at first may appear. This is not the same as “sky” or “the beyond.” The powers of heaven are astral phenomena in an apocalyptic set of words that indicate political powers on earth being shaken and crumbling as a result of God’s act on earth — both in judgment and in redemption. In the midst of political chaos the Son of Man appears as the One who is Vindicated. See Isa 34:4; Hag 2:6.
Third, 22:43 means God’s presence.
Fourth, Jesus ascended into heaven does not mean that we ascend into heaven someday to our final resting place, though this could be true. What it means is that Jesus has gone into the very presence of God.