A question that often comes up these days is "Can I fly with Mom's Urn?". The short answer is yes, as long as the urn can be X-rayed, you can bring it on the plane with you. Cremated remains may be placed in check-in luggage on some flights, but as they are irreplaceable, and airlines have a history of losing luggage, I wouldn't recommend it. If you have selected astone or bronze urn that cannot be X-rayed, TSA is not allowed to open it, and the urn won't fly. A solution would be to bring the urn to your local funeral home, where they can place the cremated remains in a temporary container for transport, and a funeral home at the other end can replace the cremated remains back in the urn. Aside from the cost of purchasing a temporary container if necessary, neither funeral home is likely to charge for this service. For the long answer to transporting cremated remains, here are two statements on the subject from TSA.
Transporting the Deceased
Traveling with Crematory Remains
We understand how painful losing a loved one is, and we respect anyone traveling with crematory remains. Passengers are allowed to carry a crematory container as part of their carry-on luggage, but the container must pass through the X-ray machine. If the container is made of a material that generates an opaque image and prevents the security screener from clearly being able to see what is inside, then the container cannot be allowed through the security checkpoint.
Out of respect to the deceased and their family and friends, under no circumstances will a screener open the container even if the passenger requests this be done. Documentation from the funeral home is not sufficient to carry a crematory container through security and onto a plane without screening.
You may transport the urn as checked baggage provided that it is successfully screened. We will screen the urn for explosive materials/devices using a variety of techniques; if cleared, it will be permitted as checked baggage only.
Some airlines do not allow cremated remains as checked baggage so please check with your air carrier before attempting to transport a crematory container in checked baggage.
Crematory containers are made from many different types of materials, all with varying thickness. At present, we cannot state for certain whether your particular crematory container can successfully pass through an X-ray machine. However, we suggest that you purchase a temporary or permanent crematory container made of a lighter weight material such as wood or plastic that can be successfully X-rayed. We will continue to work with funeral home associations to provide additional guidance in the future
http://www.tsa.gov/travelers/airtravel/specialneeds/editorial_1296.shtm