In Canada, concealment is illegal for any knife deemed to be a weapon. I don't know exactly what would be "deemed to be a weapon" (because it's not clearly defined) or what is considered "concealed," but your Delica is the one I would consider most likely to approach the perception of being a weapon (especially if you do or say something that indicates it is intended as a weapon). You may have to carry it with at least the tip and clip exposed to comply. You could call a local knife shop upon arrival to verify the best way to carry the Delica.
I don't know the laws in Costa Rica, but I was there once and my impression is that your tools would be considered normal pocket clutter there. Like most of Latin America, it is not unusual to see someone weilding a machete, even in town. I doubt anyone would remark at a 3" pocket knife.
Of course, all the normal airport common sense applies.
Enjoy your travels, and good luck.
