Dunno if this has been pointed out yet, but someone referenced World of Planes with World of Tanks, that isnt the case... World of Warplanes is from the makers of World of Tanks, and World of Planes is from the makers of Wings of Prey... confused yet?
World of Warplanes will be a free download, and you can buy a premium account and gold and all that like World of Tanks, not sure what the story is with World of Planes.