what travel documents does a 5 year old need to travel from New Jersey to Puerto Rico?

Puerto Rico is a territory of the USA, and as such no passport is required to travel to an from here. It is the same as interstate air travel. You should just make a copy of the birth certificate, in case, I have only been asked for it once in 16 years but you never know. The previous answerer is extremely misinformed.

A 5 year old is old enough to have their own PASSPORT.

Here is all the CURRENT passport/visa information you could ever use DIRECT from the U.S. GOVERNMENT.. If you have a QUESTION about passports or international travel for Amerikans.. THIS IS THE PLACE TO LOOK IT UP

http://travel.state.gov/

ITs required to have a passport for everyone