For most every day tasks I am sure they're identical to each other.
Look at this side by side. The Air and the Air 2 are nearly identical for everyday tasks. Email, browsing, Siri, etc. They're all the same on both
iPad Air 2 vs iPad Air - Speed and Benchmarks:
http://youtu.be/F35mdLPcTYc
Actually Siri was a second faster on the Air 1.
Benchmark scores are irrelevant for everyday use as you can see. It isn't twice as fast on anything. They're nearly the same for the regular user.
The only real difference is the ram which brings usable multitasking. But your regular guy watching YouTube could care less about dumping background apps and tabs on safari.
The only reason why we even see any difference is because the video shows them side by side, but if you have an iPad Air and go check out the Air 2 and start watching videos, browsing, opening the apps you use, then clearly you will not see any difference for most things you do on an iPad. To your eyes they'll be the same thing.
Now you'll come back and say you notice a huge difference but we all know that's not the case. Review after review says if you have an Air 1, an upgrade isn't worth it, they say that because of what we see in the video.
For every day use, the Air 1 and Air 2 are just about the same thing.