Hoverbout

Hoverbouts — alternatively spelt 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.

Pre-Time War
On Skaro several styles of hoverbout were used to patrol the planet and the monitor events close to spacecraft. (COMIC: Legacy of Yesteryear)

The Daleks made use of transolar discs for patrol during the 22nd century Dalek invasion of Earth. (AUDIO: Masters of Earth) A Dalek assassination squad sent in a Dalek time machine to kill the First Doctor and his companions used hoverbouts to obtain a better view of the Aridian desert. (PROSE: The Chase)

The Dalek invasion fleet preparing in the hangar to destroy the solar system with the Time Destructor was monitored from air on Kembel by Daleks in hoverbouts. (PROSE: The Mutation of Time)

The Daleks used hoverbouts to escape the destruction of a Voord spaceship, follow an escape capsule containing the First Doctor and the Chief Voord to a South American jungle, and battle Earth fighters. (PROSE: Doctor Who and the Daleks)

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)

Time War
Transolar discs were used during the Last Great Time War. (PROSE: A Prologue) They were used to pursue on Arcking. (AUDIO: The Good Master) Hoverbouts were used to travel beneath the crust of Gallifrey during the First Segment of the War. (PROSE: The Stranger)

Post-Time War
Transolar discs were salvaged during a war between humans and the New Dalek Paradigm, and were investigated at Station 7. (COMIC: The Only Good Dalek)

Bronze Aqua-Dalek units used underwater version of hoverbouts to destroy a submarine used by the Eleventh Doctor and his companions. (COMIC: The Dalek Project)

Behind the scenes

 * The vehicle has only ever been on screen in the in character segments of More Than Thirty Years in the TARDIS.
 * The Into the Dalek set includes Black Dalek with a black hoverbout, though no such Dalek appears in the episode.
 * The Doctor Who Time Zone Playset Dalek Invasion 2075AD includes a bronze Dalek with a Hoverbout.
 * Bronze Daleks aboard transolar discs are featured on both the animated YouTube trailer for Big Finish Productions' The War Doctor audio anthology, Only the Monstrous, and the cover art for The Thousand Worlds, The Heart of the Battle and The Shadow Cage.