"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
AirPods and AirPower: Everything We Know
Apple Planning Ultra-Portable?
According to Reitzes, the ultra-portables would use NAND flash memory only in order to speed boot times.
This is not the first time flash-only portables have been discussed as a possibility for Apple. In January, Digitimes claimed that Apple would be taking advnatage of Intel "Robson cache technology" which does exactly this. Flash memory is used instead of the hard disk for computer startup and launching of frequent applications. The benefits would be faster boot time and improved battery life.
In a related report Apple was said to be stocking up on NAND Flash memory earlier this month. This accumulation was presumed to be iPod-related, but could also be used towards these rumored ultra-portables.