I have an iPad Air 1 and an iPad Pro. I see no reason to upgrade to the 9.7-inch Pro. At home I use the Pro for almost all my tablet stuff. Streaming video is larger, most of the stuff I do is nicer on the big screen. Since I don't want or need the keyboard or pencil, the Pro for me is really just a bigger iPad. But at double the size of the 9.7-inch tablets, this makes a huge difference.
The Air 1st-gen, while less powerful than the Air 2 or the Pro, is still a wonderful tablet, and light enough for travel. A laptop is too heavy for my carry-on and too fragile for my checked luggage, so the iPad Air is perfect for travel, and absolutely good enough as a travel computer.
I also use the Kindle app on the Air rather than the Pro at home because it's just as easy to read on, and easier to hold, both for its weight and its size.
P.S. If I didn't have the Air 1 I would buy a 9.7-inch Pro for travel. But the upgrade is not worth the cost for the improvement.