Just retract it after using and your luggage stays clean. The hollow grind keeps the blade sharp for much longer. For more safety the knife point is rounded.
Bringing your own cutlery when you eat outside at picnics or just for takeaway food can away a huge amount of single used plastics.
You can clean the cutlery in the dishwasher. If you wash the knife and fork by hand, you should dry the fork immediately afterwards to prevent rust or limescale.