Reformer - I'm not sure what your position is on the use of the Septuagint, but in this story of Elijah leaving the earth by a whirlwind, the wording in the LXX is a bit different, and indicates that Elijah did NOT ascend into the spiritual realm of God's heaven, but only into the heaven of the earth's atmosphere.
Here it is in the LXX (IV Kings 2:1) "And it came to pass, when the Lord was going to take Eliu with a whirlwind AS IT WERE into heaven, that Eliu and Elisaie went out of Galgala." Again, in IV Kings 2:11, (LXX) it says the same thing: "And it came to pass as they were going, they went on talking; and behold, a chariot of fire, and horses of fire, and it separated between them both; and Eliu was taken up in a whirlwind AS IT WERE into heaven." So it only APPEARED as if Elijah's ascent in the whirlwind was taking him into heaven, when in reality he was being transported through the sky to another earthly location.
The conditions of this transport are remarkably similar in language to Ezekiel's experience in Ezekiel 1:4 and 3:12-14. There, it speaks of a whirlwind that comes out of the north, and says that "...the spirit lifted me up, and took me away..." Ezekiel never ascended bodily into God's presence in order to receive those visions. Elijah's transport could have been of the same nature.
There are those who prove that Elijah was actually transported to another location on earth in the whirlwind by pointing to II Chronicles 21:12-15. In that text, Elijah wrote a letter to King Jehoram of Judah, reproving the king for his past evil actions and predicting the manner of his death. This letter was written some 10 years or so after Elijah's leaving earth by the whirlwind, which shows that he was transported elsewhere on earth where neither Elisha nor the searching prophets could find him.
We are never told by scripture that Elijah was TRANSLATED (like Enoch, the solitary example of this) so that he would not see death, so the verse stipulating that it is appointed unto men once to die also applied to Elijah. He also died once, as all men have done, and must do.
It was an absolute necessity that Christ Jesus be the "Firstborn": the first resurrected one born of a woman to ascend to heaven and stand before God. As the "First-born", Christ Jesus "opened the matrix" for the rest of the children of faith to follow later on. That is why Jesus told Nicodemus in John 3:13 that "NO MAN HATH ASCENDED UP TO HEAVEN but He that came down from heaven..." If anyone HAD been able to enter heaven before Christ, then Jesus would not have been able to claim the unprecedented title of the "First-born" and the "First-begotten from among the dead".
The John 3:13 text tells us exactly which "heaven" is under consideration. Contrary to the heaven mentioned in the II Kings 2 account about Elijah, the John 3:13 text refers to the particular heaven of God's presence which the second person of the Trinity had come from. I believe Paul called it "the THIRD heaven"? (Not to be confused with the heaven of the earth's atmosphere, or the star-studded heaven of the cosmos.)
Lest anyone think that just one verse in John 3:13 is not enough proof against Elijah actually entering heaven, we also have another scripture prohibiting access for resurrected humans to the heaven of God's presence until a very specific point in time. That particular point in time is mentioned in Revelation 15:8; just after the 7 angels are given the 7 golden vials of God's wrath. "And the temple was filled with smoke from the glory of God, and from His power; AND NO MAN WAS ABLE TO ENTER INTO THE TEMPLE" (in heaven) "TILL THE SEVEN PLAGUES OF THE SEVEN ANGELS WERE FULFILLED."
This tells us that (just as Jesus told Nicodemus in John 3:13 that there had been no man that had ascended to God's heaven until then), this was also true for a length of time following Christ's ascension. These 7 vials of wrath all had to be fulfilled before resurrected men could enter God's heavenly temple.
Reformer, this is where you and I would part company, because I see scripture teaching that all these 7 vials of God's vengeance have already been poured out during the Great Tribulation years of the AD 70 era. The day when resurrected, incorruptible human forms of the saints were finally able to ascend into heaven and enter God's heavenly temple came on Pentecost day of AD 70; i.e., the 1,335th day of Daniel 12:12-13, when Daniel and the rest of the patriarchs, prophets, and the children of faith came from the east, west, north, and south and sat down in the kingdom of God (Luke 13:28-29).
Elijah had to wait until then before he could enter the heaven of God's presence in his physically-resurrected body, but I'm certain he was okay with that. He was surely one of that list of prophets who all "died in faith, not having received the promises, but having seen them afar off..." (Heb. 11:13). God wanted to "provide some better thing" for Elijah, so that he would have lots of good company when he was "made perfect" along with the rest of the saints when Christ came for the second time at the close of that Old Covenant Age.