Do your children have recorders to learn music on or do you have ethnic flutes you want to store? Save any long clear plastic tubes from packaging and use them for flute cases!
For a better and more permanent storage you will need the following PVC parts:
one piece PVC pipe inside diameter large enough for the flute to slide in easily and slightly longer than the flute when fully assembled.
One PVC cap same size as and will slide over one end of the pipe. One PVC Male threaded coupling to slide onto the other end of the pipe and one threaded cap. Only the PVC cap and the male threaded coupling which attach to opposite ends of the pipe are glued to the pipe. the threaded cap screws onto the threaded male coupling completing the project.