There is the King Pakal is falling backwards into the mouth of Xebalba. More humans depicted like the one in the Pakal Votan tomb lid can be found in other artwork not depicting anything like a spacecraft, the figure from Kerr photo number 3422 seen reclining on a platform in a similar strange position. Then in Kerr photo number K7146, a dwarf reclining on a water lily pads spread out across the head of the water lily monster, which certainly isn't an engine for a space craft.
|Detail from vase from photo : Kerr number 3422
|Detail from photo Kerr Number Kerr Number: 1184. Resurrection of infant in the otherworld.
The calendar round could denote the years AD756 or AD808 (source research.mayavase.com/)
(Actually the person lying back appears to be undergoing a transformation into an animal.)
|Detail from photo Kerr Number 7146, a dwarf blowing conch shell while lying on bed of water lily
pads which is sitting on head of water lily monster (Long nosed skeletal with lily pads emanating
from top of head) (source: http://research.mayavase.com/)