Technology!
The Jetpack is a rare to very rare item that is immensely helpful in traversing the dungeon. It can be found inside certain shops for $40,000, as a very rare drop from a crate or by bombing the wall behind the Giant Alien in Area 3. As of version 0.99.5, it cannot be equipped at the same time as a cape.
Functionality
For all intents and purposes, the Jetpack replaces the rope, spring shoes, and climbing gloves. It allows you to fly upwards in any direction by pressing and holding the jump button after jumping. The extra boost works for a short time, and recharges when you touch the ground - but not when you grab onto a ledge, or a wall with the climbing gloves. Note that flying with the Jetpack to the maximum height it can provide is typically high enough to cause falling damage if you land on the same platform or lower, so be careful when flying upwards. It has infinite usage.