Two ways an iPad is built
The front of every iPad is made of several layers. On top sits the cover glass with the touch layer that detects your fingers, and underneath it sits the screen that creates the image.
On the current iPad Air and iPad mini models these layers are bonded firmly together, and the same goes for the iPad Pro. Apple calls this “fully laminated” in the tech specs. The image seems to sit right under the surface because there is no longer any air between the glass and the screen.
The standard iPad, the one without an extra word in its name, does not have this. There the glass with the touch layer sits separately above the screen, with a narrow gap in between. That also applies to the newer generations with USB-C.

