Ashes must be buried.
Wouldn’t buried at sea count? They will still be in an urn at the bottom of the sea.
There is usually a waiting period for both bodies and ashes to be interred at Arlington National Cemetery. This is due to the number of veterans who qualify to be burried there and the number of burials that can be done each day. The two burials I’ve attended in the last 3 years had a two month delay from the vet’s death to the earliest date the body could be buried.
Veterans who served aboard the USS Arizona can request their ashes be intered within the hull of the old battleship. The ashes are placed in a water proof container and placed at the bottom of gun turret number 3. One of the recent shows about the attack on Pearl Harbor shows such an interment, which is done with respect and solemenity.
A co-worker career Navy veteran uncle recently died and his ashes were buried at sea by a Navy ship and crew. I don’t know if it was a scattering of ashes over the sea, or a version of ‘burying a body’ by casting the urn into the waters. Again, done with all military honors.