Aether was the son of Erebus. However, Damascius says that Aether, Erebus and Chaos were siblings, and the offspring of Chronos (Father Time).
The lighter and finer ones floated above and became the Bright Air (Aether and/or Ouranos) and the rarefied Wind (Chaos), while the heavier and dirtier atoms sank and became the Earth (Gaia) and the Ocean