Mass Ascension at kite festivals. Stack or arch if kites on one line.
Team is used for a group of fliers. "Mess" of kites if kites are all tangled up on the ground
, sometimes "Ballet" if kites are in the air
A group of Swallow-tailed Kite birds is known as a "brood", "kettle", "roost", "stooping", and "string" of kites.
"Stooping" seems appropriate, especially when learning stunt kite tricks!!!