What airline do bikes fly free on?

Excuse me, I was wondering if you could clarify something for me regarding airline policies. Specifically, I'm curious about which airline offers the benefit of allowing bicycles to fly for free as part of their baggage allowance. Is there a particular airline that is known for this policy, or do I need to check with individual airlines to see if they offer such a service? I'm planning a trip and would love to bring my bike with me, so any information you can provide would be greatly appreciated.