The next gen MacBook Air — expected to arrive soon with Sandy Bridge processors, Thunderbolt technology and the Lion operating system– will sell to the tune of 1.5 million units per quarter, Deutsche Bank analyst Chris Whitmore thinks.

In a note to clients — as reported by “AppleInsider” ( — he says Apple has placed orders for a total of 380,000 Sandy Bridge-based MacBook Air models this month. Roughly 55%, or 209,000, of those are expected to be the 11.6-inch models, while the remainder will be the larger 13.3-inch models. They’re expected to go on sale next month.

A MacBook Air refresh, along with the impending release of Mac OS X Lion, is expected to boost Mac sales even more, as Apple’s computers have consistently outgrown the rest of the PC market for years now. Whitmore has forecast sales of 18 million Macs in calendar year 2011, but he said Monday that he now believes his estimate is conservative.