The Air Caste is charged with holding the Tau Empire together through the [[Kor'vattra]], the Tau Empire's merchant and warfleet. Formerly functioning as messengers, these days they are the Tau Navy. The Tau of the Air Caste are the tallest and most slender of all Tau, with long, skinny limbs and hollow bones developed due to lives lived mostly in low- and zero-gravity ships and space stations. In the past, before the time of the Mont'au, the Tau that originally became the Air Caste had membranes stretching between their limbs, allowing them to glide on air currents. Tau pilots tend to be superior pilots compared to their human counterparts because they have a better depth perception and higher G-tolerance, but lack the superior battle-experience compared to the best Imperial fighter-pilots whose fighter planes have often been in service for over a century.