According to an article and pictures published in the Dutch blog onemorething.nl the next iPad Air 2 could be much thinner than the current iPad Air. Onemorething.nl claims the photos were sourced from a Chinese display supplier. Samsung besides LG and Sharp will be the supplier for display assemblies.
iPad Air is 7.5 mm thick and the iPad Air 2 is expected to be thinner than this. Also, the iPad Air 2 might have the cover glass and LCD as a single unit which is what Apple does for iPhone. As per the article -
Chemically bonding the cover glass to the LCD results in a thinner overall assembly as well as enhanced viewing angles. Those who own an iPad and a recent iPhone can see the difference when placing the devices on a flat surface and viewing them from an obtuse angle.
It is also assumed that iPad Air will have the A8 processor, include Touch ID fingerprint sensor and an upgraded the rear camera.