The iPad Air 2 used an anti-reflective coating as well. Now the Mini 4, Pro 12.9", 9.7", and Air 2 all have it. The Pro's 9.7" display reflects the least amount of light out of all of them.
From DisplayMate.com
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displays are mirrors that reflect light from everything that is illuminated anywhere in front of the screen (especially anything behind the viewers), including lamps, ceiling lights, windows, direct and indirect indoor and outdoor sunlight, which washes out the on-screen colors, degrades image contrast, and interferes with seeing the on-screen images. The lower the Screen Reflectance the better. In fact, decreasing the Screen Reflectance by 50 percent doubles the effective Contrast Ratio in Ambient Light, so it is very important.
To visually compare the differences in screen Reflectance for yourself, hold any Tablets or Smartphones side-by-side and turn off the displays so you just see the reflections. Those reflections are still there when you turn them on, and the brighter the ambient light the brighter the reflections.
The iPad Pro 9.7 has a very innovative low Reflectance screen that reflects just 1.7 percent of the ambient light by using a new Anti-Reflection AR coating. It has by far the lowest screen Reflectance of any mobile display, so its image colors and contrast in high ambient light will appear considerably better than on any other mobile display. It’s a major enhancement that reduces the reflected light glare from the screen by a very impressive factor of 3 to 1 compared to most Tablets and Smartphones.
[doublepost=1467731967][/doublepost]DisplayMate.com talking about the Air 2. -The next cutting edge development for Tablet displays arrived in 2014 on the iPad Air 2, which received a very innovative low Reflectance screen that reflects just 2.5 percent of the ambient light by using a new Anti-Reflection AR coating (together with eliminating the air gap). While this was overlooked by most consumers, reviewers, and (even) manufacturers, it was a major enhancement that reduced the reflected light glare from the screen by a very impressive 62 percent compared to the iPad Air 1 (and even more for the earlier iPads).
Don't know why iPhones haven't received it yet!