As an auto flying weapon skill, this card counts as a creature. Weapons are more powerfull than creatures because you can have only 1 at the same time or you must use a flying weapon card yo put another one.
This card is a creature which 1st turn (or more if you want to) is played in the weapon slot.
Conclution: It's cost/damage is well put there.
Comment: It seems there will be more powerfull cards in the game which will make it more strategic, how about adding a 2nd ability to the card?
A second ability seems unnecessary as it would probably:
a) Mess with the balance.
b) Mess with the simplicity of the card, which IMHO is part of it's charm and theme. It animates weapons with the magical winds provided by the False Gods of Air imbued in it's hidden gemstone, and it probably won't get much better than what it is now.
Very nice concept. Maybe second weapons will boost monos. Air unuped is overpowered because of animate weapon.
It takes 1 extra turn to play this as a 4 ATK creature at the total cost of 3
(And then needs to wait
another turn to use it's ability again), which is pretty decent considering it also can animate other weapons, which in turn is also a relatively slow process until you get multiple Flying Swords on the field.
It's damage/cost ratio as a weapon is inferior to all of the current Other weapons (including mark bonuses).
As for the 24-turns debate : chances are a deck that requires swarming the field with weapons is going to be either a OE/Animate Mono-air, Air Mark/Nova-weapon rush or a weapon-based stall.
All three risk a slow startup (drawing too few quantum sources or too many/few swords), which hinders the rainbow rush along with other possible weaknesses like PC, and most Quantum denials (BH is the most obvious case, though Discord and Pestswarm decks can mess up decks that rely on cheap weapons powered by Nova.)
Denial (Even Trident) can hurt a mono-air, and PC or CC (especially non-damage CC like BB, RT, or Artic Squid/Wardens) can slow the deck down for too long.
Stalls can deal better with the windup period, but usually will require you to duo and will probably go closer to the possible 24> turns than the other two, with the result of being more effective against more decks.
While it's not OP, Flying Sword probably will be the core card of decks that use it, and can be countered appropriately by the right decks.