The Hover Pack is a power-up used by Bentley as a jetpack that allows him to gain height, travel large distances or both. It could be purchased from ThiefNet for 1200 coins in Episode 6: He Who Tames the Iron Horse of Sly 2: Band of Thieves, 300 coins on day 2 of Episode 2: Rumble Down Under of Sly 3: Honor Among Thieves and was a default ability in Sly Cooper: Thieves in Time.
In Sly 2, it used a small amount of the Gadget Meter; in Sly 3 it uses none of the Gadget Meter; and in Thieves in Time, like other power-ups, uses all of the Gadget Meter, allowing approximately four seconds of flight before it needs to be recharged.
The hover pack serves different purposes in Sly 2: Band of Thieves, verses Sly 3: Honor Among Thieves and Sly Cooper: Thieves in Time, due to Bentley being confined to a wheelchair. In Sly 2, the hover pack drains the Gadget Meter by a small amount but its usage is limited to approximately four seconds per use. It is used primarily to gain height, but can be used to travel a large distance.
In Sly 3, the hover pack gives Bentley's wheelchair the ability to quadruple jump (three bursts after the initial jump), and has unlimited usage, until the wheelchair touches the ground. The hover pack is automatically assigned to and cannot be assigned to any other button.
In Sly Cooper: Thieves in Time Bentley has the hover pack at the beginning of the game. It provides a small height boost and allows Bentley to float a longer distance laterally than with a single jump. It consumes the Gadget Meter, which then refills quickly after Bentley stops hovering. It can be upgraded with power-ups.