Can I bring my metal walking pole on an airplane?
It is up to the airline company and the security. A metal walking stick has been classified as a ski pole, which is prohibited, but has also been classed as a walking aid, which is not. Normally it wouldn't be allowed as a hand luggage, but would be allowed as hold baggage. You wouldn't take the chance if it would be confiscated so better to put it in the cargo hold baggage. Perhaps you can give some extra protection by putting them in cardboard mailing tubes or wrapping them with foil.
Nothing unnecessary just exactly what you need for your Camino