Can I travel to another state with my 13 year old brother without our parents? do I need any document?

If you are an adult and have permission from your parents to do so, it would be fine. However if you take your brother without permission and your parent wanted to call the police and say you kidnapped him, you would be arrested.

Mary has good points...if there were an accident you would not be able to give permission to treat. You should have a temporary power of attorney for health.
no i dont think u can and ur brother needs a passport


Answer:
you should let your parents answer that one. and how old are you?
I don't know the legality portion of it, but just wanted to mention three key things-

1. have your parents permission
2. have insurance information for him in the unfortunate event something happens
3. a signed note from your parents saying if your brother needed medical attention, you had permission to use the insurance card, but to call them with their cell phone numbers, etc
You should have no trouble traveling. If you planned to move. That is a different story. The only problem would be if your brother needed medical care. Legally you can't sign for it. You are not the legal parent. Any airline allows minors to fly. Even without the parents.
Of course you can go out of state legally with your Brother.. As long as your mom knows you are coming in case you do get pulled over and she can explain it to the cops.. Otherwise they may think you are trying to kidnap him.. & you do not need a passport to go from state to state.. Good luck