Rehearsal Wings

Hanging on a rack in the hall outside wardrobe:

It's not a kite with suspenders, they are the "rehearsal wings" for Oberon and Titania (quite different than training wheels). They wear their wings for a few sections of the ballet and therefore need to rehearse with them. They're quite large and unwieldy, so you can imagine what it would feel like to have something like that strapped to your back while trying to move.