The screen has been improved from the previous iPad Air. Early hands on reports say it is a noticeable improvement.
If you are asking whether they increased the resolution, then no they did not. However the iPad Air already well exceeds the iPad 6+ In total pixels. If you consider the way you hold the device compared to a phone, the PPI is acceptable.
They've finally laminated the display to the glass with the Air 2 and are using the newer anti-reflective coating, so it should look just as vibrant as the 6 & 6 Plus do.
I don't think it's technically "Retina HD" because it doesn't have dual domain pixels, but this is primarily a technique to improve viewing angles. The display lamination is probably the more important change, though, because that's largely what makes it look like the 6/6 Plus displays are "painted on" the screen.
Wondering the same thing. I was really hoping it would have the Retina HD (which is pretty much just better viewing angles, improved polarizer, and much higher contrast ratio) but there's no mention of it on the tech specs. I figured that if the contrast ratio/viewing angles/polarizer was improved they would've mentioned it on the product page like they did with the iPhones, but there's no sign of it anywhere.
I suppose the laminated display will make the screen seem closer to the surface and might help when you're using it in a glare-y environment, but I was really hoping for the improved contrast ratio. Shame, because the blacks on the iPad look washed out and gray compared to the deep blacks on my iPhone with the Retina HD.