Does {pithing needle} stop aetherling. If not what does?
As long as it doesn't get countered, needle hits the Aetherling. They can flip it in response, but when it comes back it's just a 4/5.
But doesn't Aetherling have mana abilities?
It has abilities that cost mana to activate, but it doesn't have mana abilities.
605.1a (http://imtgapp.com/forum/index.php?action=imtg;area=rule;number=605.1a): An activated ability is a mana ability if it meets three criteria: it doesn't have a target, it could put mana into a player's mana pool when it resolves, and it's not a loyalty ability. (See rule 606, "Loyalty Abilities.")