What paint is safe to use to decorate hard-sided luggage?

Any craft paint will work. Just be sure to seal it so it doesn't peel off. I just returned from a trip myself, and even flying first class with priority, the airline still mishandled one of my bags and now looking into new luggage. And I will do the same thing - paint or embellish so it is easily recognizable amongst the sea of bags on the luggage turnstiles. My girlfriends husband worked the ramps as a second job (they wanted the employee flight benefits), and the stories they tell are hair raising. There is always one baggage handler with an axe to grind unfortunately. Murphy's Law prevails and I always get "that guy" on my flights! 🌞

Naomie is exactly correct, most any paint will work, the key is to seal it well so it is protected as much as possible. I'd think bright yellow or pick would be a stand out among alll the ho-hum black, grey and brown luggage out there on the turnstile.

If the suitcase has a lot of ridges on the surface, consider a spray paint/ spray sealer. That will be easier to get in the crevices.

I use a sharpie to write my initials on mine. I do wish I didn’t have a black suitcase! There are so many sharpie colors, and it is easy to go back over it if it wears off or starts to fade.