IS:
It doesn’t make a difference what it actually looked like per se. The pasuk says “???? ??? ?? ????? ???”. What matters is what we are saying it did. It could be that Eliyahu used the maaseh merkava to go up. I’m not a mekubel so I don’t know how these things work, but I see that Eliyahu went up in a ???? which is also found Yechezkel 1:4.
What matters is if the purpose of this vehicle was to bring Eliyahu to shamayim or to another planet. Without any mekor, for saying such a chidush, you need to bring a proof that it is anything other than what is commonly explained.