When used, Steve hops upward, unfurls his Elytra, and attaches a Firework Rocket on it, propelling him upward. The move functions somewhat like a combination of Brawl's glide mechanic and resembles that of Pit's Wings of Icarus: aiming the move upward grants the highest vertical recovery, but causes Steve to stall when at the move's apex and enter freefall, in addition to minimal horizontal distance; the move itself is more suited to horizontal recovery. A damaging hitbox is created on startup (as Steve lights the rocket). After the rocket is used up, hitting a wall or ceiling will cause Steve to crash and enter free fall. Dodging or attacking during the glide will cancel Elytra, causing Steve to fall but letting him retain the ability to move side to side.
The elytra is an item added in the Java Edition 1.9 update, where it can be found in treasure rooms on End Ships. When falling, the elytra can be used by pressing jump and the player will immediately start gliding. Starting in 1.11, firework rockets can be used to increase the elytra's propulsion, allowing the player to fly for a longer period of time.
An unenchanted elytra can be used for 7 minutes and 11 seconds before it stops working, at which point it needs to be repaired with either another elytra or phantom membranes.
In the real world, an elytron (pluralised as elytra) is a hardened forewing on insects that closes over and protect the more delicate hindwings. Elytra can not be used for powered flight but can be used to glide and slow descent.