The Intention Craft is an aircraft designed by Lord Asriel in the war against the Authority. The device is powered by the intention of the controller and their daemon using hand holds.
The Intention Craft is a "flying" machine, but has no engine or wings (some fans have speculated that it uses anti-gravity). It has a cockpit and controls like a gyropter (helicopter from one of Pullman's fantasy worlds) and six bug-like legs. However, there is a helmet and leather wrapped mechanism on a string, so that the craft can be controlled by the driver's intentions. It can only be used by a being with a dæmon, as the Daemon bites on the mechanism attached to the string. At least two exist, one more advanced than the other.
The Intention Craft appears to be armed with very advanced weaponry. It was able destroy enemy artillery shells before they could hit their targets and wipe out several enemy aircraft before they could respond. Its weapon resembles a laser or particle beam. The technology used to create both the craft (which presumably moves via some kind of anti-gravity system) and its weaponry appears to be exceptionally advanced for our world and should thus have been aeons ahead of Asriel's universe. It is never explained how he was able to develop such advanced technology in such a short time (although fans have speculated he may have either got it from one of the many universes his army amassed from or secretly developed it himself; he had already developed considerably advanced equipment before which enabled him to open up a portal between universes).
It is used by Mrs Coulter to escape Lord Asriel's fortress, by Lord Asriel, to rescue Mrs. Coulter, then again by Mrs. Coulter to reach the Clouded Mountain, in order to trick the Regent of Heaven, Metatron.