Grandparents want to take an 11 year possibly
to Aruba. I don't you don't have to have a passport to enter at this time, but in checking since he will not have the same last name as the traveling grandparents. will there need to be a letter of authorization from the parents. Now here is the real problem. The mother is remarried, different last name as the child and the father has not been around for 11 years even though he has joint custody.

When I was researching this week there was information about children and passports. You may want to read what www.visalady.com has to say.

You should also travel with some letter or similar authorizing you to make medical decisions on the trip. I kept one in my wallet for the many trips I took with nieces and nephews. (In many places) the child can not receive medical treatment without permission from a parent.

To be on the safe side, get a notorized letter from the mother stating she has primary custody, her permission to take the grandchild out of the country, and her permission to make medical decisions.

For more information go to www.state.gov

I guess it depends on when the trip to Aruba is. Looks like passports are required starting in December of this year.
http://travel.state.gov/travel/cbpmc/cbpmc_2224.html

Names will not matter - I have a different last name than my kids.

Letter authorizing medical treatment is important. As far as letter authorizing taking child out of country, I know it is always recommended and I have taken one (when going to Europe with our daughter without him) and my mother has taken a letter when traveling with our daughter. It has never been requested.

I would advise anyone to get a passport - will soon be required for travel anywhere and is good ID to have anyway.

I have found that in this post 9/11 world a passport just makes life easier.
And yes, I would sure as everything have letters permitting the child to travel.