How does putting a pet in airline cargo work, what's it like to do that?

In a couple months I will be shipping my cat through cargo on an airplane. So what's that like, what should I expect? Will they treat her like a checked bag? Should I put a lock on her kennel? Should I attach food and water bowls? I want to, but won't they spill? Anyone have experience with doing this? How'd your pet hold up? How does it work, how do you get them back?

Ask the airline you're travelling with - they'll advise on what happens, and what you need to provide.

Bad idea, unless you luck out with a crew member who appreciates pets it will be tossed into a noisy, unheated and low air pressure cargo hold, possibly next to a hostile and threatening dog, no food or water. And if you have a lawyer read your ticket, no right to sue when your pet arrives dead after this torture.

Make sure the bag is airtight. You don't want it to leak

If the airline offer this service, they are fully aware of how to treat animals, they are not put in a noisy unseated low pressure cargo hold, rather it will be pressured to the same as the aircraft main cabin, probably at the same temperature. They will expect you to arrive with your cat in an approved container, if it is a long flight, then providing food and water is your responsibility, most animals can survive without food, but may need water to stop getting dehydrated, dry food would be best.

I'm assuming you are traveling with your pet.

The airlines will treat the kitteh with lots of TLC (Tender Loving Care.) They want to see your kitteh get through airline travel with as little stress as possible.

When you check-in, the animal and the accompanying kennel will be inspected by security with you present. When cleared the kitteh will be properly secured in their kennel and handed back over to the airline for transport.

1.) "Will they treat her like a checked bag?"

No. They will treat kennels differently. They are placed in a lighted climate-controlled area of the aircraft's cargo section.

2.) "Should I put a lock on her kennel?"

ZIpties will work. Keep several handy until the kiitteh and the kennel is cleared.

3.) "Should I attach food and water bowls?"

Recommended if it is a long trip.

4.) " I want to, but won't they spill?"

The kennel will be kept in an upright position. The rampers will make sure of this. Spillage will be minimal.

You MUST discuss all of this with the airline. We can all offer general advice and information, but in the end your pet and her travel-cage MUST comply with the regulations of that specific airline.
They will TELL you what kind of cage you should use, and whatever they tell you, DO IT. Don't think, 'Oh, the one I've got already is kind of like what they say; I'm sure it'll be OK'. Because it might NOT be OK, and the airline can refuse to carry your pet if you haven't fully complied with their rules.

You didn't say whether this is an internal or international flight, so I hope it's internal. But if it's international you have a LOT of work and bureaucracy ahead of you, so don't waste a moment.