How does the propagation of gravitational waves contrast with sound waves?

Answer

Gravitational waves are the modulation of spacetime itself, unlike sound waves which require a medium like air.

Gravitational waves are not like sound waves which require a medium like air; instead, they are the modulation of the medium—spacetime—itself.

How does the propagation of gravitational waves contrast with sound waves?
propagationspacetimewavegravitational wave