What does my 5yr old child rewire for domestic flights id wise? Also booster seats, can I bring it into the plane and stored or must I check it with my luggage and placed under the plane.

You can bring it with you on the plane, when TSA check out, feel free to show them your kid birth certificate, you will be fine

Thank you Victor and James, very much appreciated!

Bring the booster and their birth certificate just in case.

If your child sits on the booster seat you can bring it on the plane. They should not need any form of ID however I would definitely have their birth certificate or passport just in case to avoid any problems.