Parachute

A parachute is a cloth canopy which fills with air, therefore allowing the person attached to it to descend slowly.

Draco Malfoy once said that it was a shame that Harry Potter's Firebolt didn't come with one of these because he would need it incase he encountered another Dementor (Harry's previous encounter with a Dementor resulted in him falling off of his broomstick from high above the ground).

Appearances
Harry Potter and the Prisoner of Azkaban