Apple may be selling enough MacBook Airs to make it a cornerstone of its computer business, JPMorgan analyst Mark Moskowitz said in a research note Thursday. Based on an understanding that first quarter sales of the ultraportable were sequentially up 2.9 percent to 432,000 where Macs as a whole were down 10.5 percent, he expected Apple to move as many as 700,000 of the notebooks each quarter in the near future. He had already seen it making $2.2 billion in revenue for Apple but now saw it topping $3 billion or more.