You will be VERY hard-pressed to notice the difference in speed between the iPad and the iPad Air.
The displays are mostly the same: ~few pixels and .2" difference.
The weight is almost the same.
They both can use the Apple Pencil.
The speed difference isn't worth $170.
For $60 less than the 64gb standard Air (499) you can get the 128gb iPad ($439)
(FWIW... I'm a software developer and I own both to test my apps with... I'm not impressed with the Air)