OWC released a SandForce SF-2281 based 2011 MacBook Air SSD upgrade earlier this year in 120GB and 240GB capacities (the Mercury Aura Pro Express 6G). Using Hynix 2x-nm NAND (64GB packages with 8GB die) OWC is now shipping a 480GB version for $1149. If you need a ton of capacity for your MacBook Air, this is really the only solution.