And it came to pass, when the Lord was about to take up Elijah into heaven by a whirlwind, that Elijah went with Elisha from Gilgal. 2 Then Elijah said to Elisha, “Stay here, please, for the Lord has sent me on to Bethel.”
But Elisha said, “As the Lord lives, and as your soul lives, I will not leave you!” So they went down to Bethel.
3 Now the sons of the prophets who were at Bethel came out to Elisha, and said to him, “Do you know that the Lord will take away your master from over you today?”
And he said, “Yes, I know; keep silent!”
There are a several things that come to mind apparently this was somewhat common knowledge. Elijah, Elijah, and the sons of the prophets each knew that Elijah would soon be carried into heaven by a whirlwind.
And it came to pass, as they still went on, and talked, that, behold, there appeared a chariot of fire, and horses of fire, and parted them both asunder; and Elijah went up by a whirlwind into heaven.
This sounds like prophet Elijah was an extraterrestrial and when his mission was complete he got a lift of the planet by an Unidentified Flying Object aka chariot of fire, Golden Horse etc.