Saw something about this in a TV program some time ago....
Maybe the Queen of Sheba stole it during her visit with Solomon.
IIRC, the story is that Solomon flew it there.
The Sign and the Seal
Graham Hancock
https://en.wikipedia.org/wiki/The_Sign_and_the_Seal
The Ethiopian Orthodox Tewahedo Church claims to possess the Ark of the Covenant, or Tabot, in Axum. The object is currently kept under guard in a treasury near the Church of Our Lady Mary of Zion. Replicas of the Axum tabot are kept in every Ethiopian Orthodox Tewahedo church, each with its own dedication to a particular saint; the most popular of these include Mary, George and Michael.[25]
The Kebra Nagast was composed to legitimise the Solomonic dynasty, which ruled the Ethiopian Empire following its establishment in 1270. It narrates how the real Ark of the Covenant was brought to Ethiopia by Menelik I with divine assistance, while a forgery was left in the Temple in Jerusalem. Although the Kebra Nagast is the best-known account of this belief, it predates the document. Abu al-Makarim, writing in the last quarter of the twelfth century, makes one early reference to this belief that they possessed the Ark. “The Abyssinians possess also the Ark of the Covenant”, he wrote, and, after a description of the object, describes how the liturgy is celebrated upon the Ark four times a year, “on the feast of the great nativity, on the feast of the glorious Baptism, on the feast of the holy Resurrection, and on the feast of the illuminating Cross.”[26]
In his 1992 book The Sign and the Seal, British writer Graham Hancock suggests, contrary to the Kebra Nagast, that the ark spent several years in Egypt before it came to Ethiopia via the Nile River, where it was kept in the islands of Lake Tana for about four hundred years and finally taken to Axum.[27] Archaeologist John Holladay of the University of Toronto called Hancock’s theory “garbage and hogwash,” while Edward Ullendorff, a former Professor of Ethiopian Studies at the University of London, said he “wasted a lot of time reading it.”[28]
https://en.wikipedia.org/wiki/Ark_of_the_Covenant