The next version of the MacBook Air with upgraded Intel processors could appear in the Fall of this year at the earliest, if a leaked Intel processor roadmap is to be believed. The Intel roadmap, published by VR-Zone (via MacRumors) shows that the next version of an appropriate mobile processor chip for the MacBook Air is set for release in the third quarter of this year. The processor, identified as an i5-4260U Haswell chip with increased speed, is shown on the roadmap for Q3, with Broadwell processors (the successor to Haswell), not launching until Q1 2015. It is unclear, however, what chip would be included in the high end MacBook Air models.
The report also points towards the next version of the Retina Display MacBook Pro, and suggests that while speed bumped Haswell processors could be included in the line this year, it is unlikely that a Broadwell equipped model would launch until next year. Intel itself has apparently pushed back the Broadwell chip release schedule, meaning that there likely will be no new Macs equipped with these processors until 2015 at the earliest, indicating that 2014 Macs will likely all be Haswell based speed bumps.