Regarding the eschatological return of Elijah, it is interesting to note Seder Olam 17. Milikowski dates the Seder Olam to the 2nd cent. (attributed to R. Yose ben Halaphta). Here there is not just one return of Elijah, but two – during the days of the messiah, and later when “Gog will arrive.” This is significant for Christian eschatology and beliefs on the return of Elijah, given that the Gospels’ equation of John the Baptist with Elijah (or one who came in the “spirit and power of Elijah”) and Rev. 11’s two witnesses, who are patterned for a large part after Elijah, and who are said to be martyred by the Antichrist. Here is the text of the Seder Olam Rabbah:
In the second year of Ahaziah (King of Israel) Elijah was hidden away and is not seen until the messiah comes. In the days of the messiah he will be seen and hidden away a second time and will not be seen until Gog will arrive. At present he records the deeds of all generations.
אחזיהו בנ אחאב מלך שנתים ובשנה השנית לאחזיהו גיגנז אליהו ואינו נראה עד שיבוא משיח ובימות המשיח נראה וניגנז שינית ואינו נראה עד שיבא גוג ועכשו הוא כותב מעשה כל הדורות כולן
Translation by Chayim Milikowski, “Trajectories of Return, Restoration and Redemption in Rabbinic Judaism: Elijah, the Messiah, the War of Gog and the World to Come.” Pages 265-280 in Restoration: Old Testament, Jewish, and Christian Perspectives (ed. James M. Scott.; Supplements to the Journal for the Study of Judaism 72; Leiden: Brill, 2001), 267. Hebrew text of Seder Olam 17 from Joseph Milikowski, “Seder Olam: A Rabbinic Chronography” (Ph.D. diss. Yale University, 1981), 323-324.
The text is as follows in Heinrich W. Guggenheimer’s edition:
אֲחַזְיָה בֶן־אַחְב מָלַךְ שְׁנָתָיַם. וּבַשָּׁנָה הַשֵּׁנִית לְאֲחַזְיָה נִגְנָז אֵלִיָּהוּ וְלֹא נִרְאֶיה עַד שֶׁיָּבֹא מֶלֶךְ הַמָּשִׁיחַ וְנִרְאֶה ונִגְנָז שְׁנִיָּה עַד שֶׁיָּבֹא גוֹג וּמָגוג. וְעַכְשָׁיו הוּא כוֹתֵב מַעשֵׂה כָל־הַדּוֹרוֹת כֻּלָּם וָיָּמָת כִּדְבַר־ייי אֲשֶׁר־דִּבֵּר אֵלִיָּהוּ וגו׳.
Aḥaziah ben Aḥab ruled for two years. In Aḥaziah’s second year, Elijah was hidden and will not be seen again until King Messiah will come, then he will be seen, then hidden a second time until Gog and Magog come. But now he writes down the deeds of all generations. (2Kings 1:17) “He (Aḥaziah) died, following the Eternal’s word that Elijah had spoken.”
Seder Olam: The Rabbinic View of Biblical Chronology (Lanham, MD: Rowman & Littlefield, 1998), 153-155.
Note also that according to Seder Olam, “In the year 13 of Aḥab there was a great famine in Samaria for three years, followed by war with Ben Hadad for 2 1/2 years” (Guggenheimer, 154).