Hoverbouts — also spelled as hovabouts and also known as transolar discs — were small circular flying platforms with a railing around the edge, used by Daleks for operation within a planetary atmosphere, in close planetary orbit and within close to medium range of a Dalek spacecraft.
Daleks aboard transolar discs were used to patrol around Dalek-held planets and in groups to attack spacecraft. (AUDIO: The Human Factor) They were also used to attack the enemy human forces attempting to breach the Dalek-held facility Project Infinity on Lopra Minor. (AUDIO: Project Infinity)
In an alternate timeline, President Nigel Rochester owned a functioning transolar disc, which he used to take the Sixth Doctor on an aerial tour of London. The vehicle was later destroyed by Rochester, who claimed that it was "bugged" with a listening device. (AUDIO: Jubilee)