pretty sure it was only quan who insisted thanos could fly/teleport using personal power alone, i've even had a pm debate of sorts telling him it wasn't shown on panel without doubt.
eternals can do it, but thanos hasn't shown to use any of those techniques without apparent tech a lot, and the times he has it's been ambiguous since he has miniaturized tech on his costume....even a nuclear bomb with a high yield and the like.
(thanos' utility belt > batman's biscuits )