Chosen Solution

I know that the iPad mini generation 1 and 2 use the same digitizer/glass, can the iPad air generations 1, 2, and 3 use the same?

Unfortunately, the iPad Airs do not have this cross compatibility. The iPad Air 1 used a separate LCD and glass/digitizer assembly, so either one can be replaced independently of the other. With the introduction of the iPad Air 2 and 3, Apple moved to using a fused LCD and digitizer assembly, just like all iPhones past the iPhone 4. This was to cut down on thickness and weight, however, it also removes compatibility between this model and the iPad Air 1. Make sure if you are replacing one that you get the correct model. The digitizer/glass for the iPad 2 is unfortunately more expensive, but it also includes an LCD, which is where the cost is coming from. Hope this Helps.