The differences between these two are small(ish), I guess it depends all on what you would like to-do with the device.
These two devices look and feel the same, use the same accessories, so from an outside perspective you wouldn’t see the difference (really).
Here 5 categories and the differences:
CPU & Ram:
iPad Pro: A10x 4Gig
iPad Air: A12 3Gig
Performance (CPU) wise the Air is 10-13% faster.
Speakers:
iPad Pro: 4 (2 on each side – Self switching for Stereo)
iPad Air: 2 (At bottom)
Camera: (back)
iPad Pro: 12MP Record 4K Flash Camera Bump
iPad Air: 8MP Record 1080P No Flash No Camera Bump
Screen:
The iPad Pro support ProMotion, you will see the difference when you draw (as artist), with video, web browsing and note taking the Air would work, the other side as well, if you never used ProMotion, you wouldn’t miss it, the Air isn’t bad at all.
Connectivity:
iPad Pro: Bluetooth 4.2
iPad Air: Bluetooth 5
Not allot of devices support Bluetooth 5 yet, the new AirPods would sound bit better, but I doubt you would hear the difference.
To summerize:
I would say if you would like to use it for a note taking device and generic tablet use (office, reading, YouTube and Netflix) then go for the Air, but if you want to draw (arty stuff), and use it for the more graphic intense programs and games, then go for the Pro.
For me the Pro is the answer (and why I have it from 2017), the sound is amazing, I use it with the keyboard, and it is my main computing & entertainment device when not in the office. I set myself a challenge to only use the Pro for 3 months, and I managed much better than I tought. (Challenge coming from 2012, only did it last year). With the new iPadOS coming in September, that would solve the last few frustrations for me, maybe I’m not going to use my Mac after that.
General:
Maybe have a look at Tom Solid’s chanel on YouTube for note taking programs, I found it very useful, especially this one: (help made up my mind)
What I saw students do, take a picture of the handbook, pull that picture of the page into note taking app, and write notes ontop of image, then also record the lecture, the audio is in sync with what you have written, so when you look back, you can figure out something if your short hand was too short…
I bought this back cover: (using Scott Shipping)
https://www.amazon.com/dp/B07215MYS4/ref=cm_sw_em_r_mt_dp_U_FTUgDb0D4W3XB
The color matches with the Apple keyboard and normal SmartCover.
You are more than welcome to PM me or ask questions, if there is something spesific.