By constraint on the relation between the body and space or ether, and by cognitive absorption on the lightness of cotton, one can acquire the ability to traverse through space.
One can interpret this Sutra to either objectively imply levitation of the physical body, making it as light as cotton fiber therefore releasing the hold of gravity on the body or subjectively imply the ability to travel through the space element which is the medium where not only all of the elements have their existence and expression but also distinguishes all elements from one another (i.e. giving the ‘space’ for them to coexist). To travel through the space element would be akin to astral travelling, moving from one space destination to another.
Words in themselves can have or can be amenable to both objective and subjective meanings and interpretations.
When we lose our sense of gratitude and light-heartedness we subject ourselves to gravity and become grave. We become dead to our connection to all things and bury our greatest treasure under the heaviness of emotional morass, our Inner Peace.