I've always put them with boards and other gear but I think you could have them as a carry on luggage. But check at the Bag Drop desk before going through security.
Here's some ryanair terms in case you haven't read those.
Passengers are not permitted to carry the following articles into the security restricted area and the cabin of an aircraft:
8.10.1.2 Pointed/edged Weapons & Sharp Objects; pointed or bladed articles capable of causing injury, including axes & hatchets, cleavers, arrows and darts, crampons (grappling iron, hooked bar of iron, or plate with iron spikes used in mountaineering), harpoons & spears, ice axes & ice picks, ice skates, knives with blades of more than 6 cms including lockable or flick knives, ceremonial, religious and hunting knives, made of metal or any other material strong enough to be used as a potential weapon, meat cleavers, machetes, open razors and blades (excluding safety or disposable razors with blades enclosed in cartridge), sabres, swords and swordsticks, scalpels, scissors with blades more than 6 cms as measured from the fulcrum, ski and walking/hiking poles, throwing stars, tradesman's tools with a blade or a shaft of more than 6 cms that have the potential to be used as a pointed or edged weapon, e.g. drills and drill bits, box cutters, utility knives, all saws, screwdrivers, chisels, crowbars, hammers, pliers, wrenches/spanners, blow torches.
8.10.1.3 Blunt Instruments: any blunt instrument capable of causing injury, including tennis rackets, baseball and softball bats, clubs or batons - rigid or flexible - e.g. billy clubs, blackjacks (truncheon of leather covered lead with flexible shaft), night sticks & batons, cricket bats, golf clubs, hockey and hurley sticks, lacrosse sticks, kayak and canoe paddles, skateboards, billiard, snooker and pool cues, fishing rods, martial arts equipment, e.g. knuckle dusters, clubs, coshes, rice flails, num-chucks, kubatons, kubasaunts.