“Customers are more curious but less willing to buy the MacBook Air than they were the original MacBook,” Munster writes in a report to clients issued this morning. “We believe that 16% of Macs by the end of calendar year 2008 will be MacBook Air.”

Munster and his team spoke to 20 Apple specialists on Monday. The impression they got was that MacBook Air sales are coming over and above the MacBook’s, and not cannibalizing Apple’s most popular model. He writes:

According to the resellers we spoke to, the MacBook Air has a smaller but separate target market than the MacBook. Most described the market as a group that prioritizes mobility and is less price sensitive than the MacBook market. One reseller referred to MacBook Air as the first “Executive Mac.”

Munster expects Mac sales overall to fall somewhat after the white-hot Christmas quarter, which is in line with the guidance Apple gave in its last quarterly earnings report. He’s modeling an 18 percent drop. However, the resellers he spoke with say on average that Mac sales are flat — which if it holds up would be very good news for the company. Specifically, 35 percent of those surveyed said Mac sales are up, 45 percent said they were down and 20 percent expected them to be flat for the March quarter.

“Our January was very strong,” one reseller told Munster, “and February is starting out strong. Our March quarter will likely be better than our December quarter.”

Munster notes, however, that the salespeople he spoke with have a better grasp on product interest and day-to-day sales than they do the big picture of the business.