Market research firm NPD estimates that Apple's MacBook Air grabbed 56 percent of the U.S. thin-and-light notebook market in the first five months of 2013, according to CNet. The remainder of the market was split between assorted Ultrabook manufacturers.
NPD's figures don't yet take into account the release of Apple's newest MacBook Airs, which leverage Intel's new Haswell processors. The 2013 models were designed to maximize battery life, with an advertised 12 hours of juice in the case of the 13-inch model.
AppleInsider found the 11-inch MacBook Air to not only live up to Apple's claims, but surpass them by some measure.
Already a leader in the mobile computing sector, Apple has also been able to somewhat buck the trend that has seen the traditional computing segment in steep decline. One report from earlier this year estimated that Apple's Mac line generates more profit than the other top five PC makers combined.