Most wood, plastic, or non-lead lined ceramic urns can pass through the TSA's security screenings. Generally, most airlines will allow you to bring a cremation urn as a carry-on provided it passes through the security screenings. Out of respect for the deceased and family, airport security personnel will never open the cremation container. This is why it is important to choose an urn which will pass through the x-ray screening.
Here is a quote from letter from the TSA (Transport Security Administration) to the International Cemetery, Cremation, and Funeral Association addressing this very issue:
TSA recommends that consumers purchase a temporary container made of wood, plastic or non-lead lined ceramic for transporting their loved one's remains.
- Bob Kapp
Department of Homeland Security
Transportation Security Administration
Denver International Airport
From the TSA's page on Transporting the Deceased: (Page was removed, now links here)
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 Transportation Security Officer 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 an officer 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.
We've found that the best solution for air travel is our TSA-approved fabric cremation urns.