J.P. Morgan analyst Mark Moskowitz tells clients in a note — as reported by “CNN Money” (http://macte.ch/Z50CD) — says he sees the MacBook Air as an US$3 billion business for Apple.

Apple shipped 432,000 MacBook Air units in the first quarter of 2011, and Moskowitz expects that to grow to an average 700,000 units over the next four quarters. At an average selling price of US$1,500, that’s $3.22 billion a year, which could tack another $0.30 on Apple’s earnings per share. A new rev of the MacBook Air with Sandy Bridge processors and Thunderbolt technology is expected any day now.

“In our view, the MacBook Air increasingly will be recognized as offering users tablet-like functionality — ultra-portability, thinness, and instant-on — while offering an integrated keyboard and a full computing applications suite to complete professional work-related tasks,” Moskowitz says. “Given the underwhelming performance of the non-Apple tablets in the tablet market so far, we expect more PC vendors to shift focus to the ultra-thin notebook PC (based on SSD storage).”