Flying rings was a gymnastic event similar to still rings

Rings (gymnastics)

The rings, also known as still rings , is an artistic gymnastics apparatus and the event that uses it. It is traditionally used only by male gymnasts, due to its extreme upper-body strength requirements...

, but with the performer gripping a pair of rings, approximately shoulder width apart, and swinging - from the point of suspension of the rings - while executing a series of stunts.
Whereas still rings are now suspended from a support almost 19 feet above the floor, flying rings – also used as still rings in the past – were on cables up to 22 feet in length - the extra four feet allowing the gymnast to swing through an impressive arc.