Wanted to take the assembled [https://www.printables.com/model/572421-3d-printable-jet-engine](https://www.printables.com/model/572421-3d-printable-jet-engine) from CATIAV5FTW with me on a plane ride, so to be safe I printed two “end caps” and connected them with cut and bent 3mm cardboard - the kind used in most shipping boxes.

The caps have conic depressions that match the spinner and nozzle cones and hold the engine directly centered; I stuffed in some foam and then used tape to fix the cardboard in place.

I left part of the cover as more easily-openable external “door” to be able to access the content without taking it all apart, for example for airport security inspections.

To assemble, get a piece of cardboard roughly 38cm (15 inch) long. It should ideally be around 75cm (30 inches) wide for a full case, but you can also combine multiple pieces together. The cardboard bends should be around 9cm (3.5 inch) apart.

Used this successfully inside a carry-on on a long flight.