"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
Accessory Manufacturer Claims 15-Inch MacBook Air Coming in April
And what is coming? If you take our source’s word for it, a 15-inch MacBook Air with ports on both sides, no optical drive and no ethernet cable.The source is reportedly involved in "MacBook docking solutions", and while Apple almost certainly hasn't shared any specific information with the source, he does obviously have a strong interest in acquiring such information and may even have access to sources who could provide estimates of Apple's plans. That said, the source may simply be reiterating a previous rumor that had claimed new 13-inch and 15-inch MacBook Pro models with thinner MacBook Air-like form factors would be launching in April.
While our source wasn’t certain that this would completely destroy the Pro (he also stated that Apple might hold on to the 17-inch model, which would make sense for the sizeable audience of professional editors out there), he was fairly sure that the shakeup will happen in April. To that end, our source’s company’s got its manufacturers on standby to be able to make and ship a new product lineup inside of 90 days.
One other question still remaining is chip availability from Intel. With delays in the launch of the chip manufacturer's new Ivy Bridge platform and uncertainty about whether these thinner MacBook Pro or larger MacBook Air products would run traditional mobile chips as found in the current MacBook Pro or ultra low voltage chips as found in the MacBook Air, it is not entirely clear when chips for the new machines will become available.