Are collapsible hangers restricted for their shape?

No — they're a solid item with no restriction, the same as any ordinary packing accessory.

Collapsible Hanger

Collapsible travel hangers are allowed in carry-on and checked bags without restriction.

Carry-on

Allowed

Checked

Allowed

Allowed. A collapsible or folding travel hanger is a solid item with no restriction.

Allowed. No restriction in checked baggage.

Are collapsible hangers restricted for their shape?: No — they're a solid item with no restriction, the same as any ordinary packing accessory.