I was really happy with the now discontinued 12" macbook. Yes it was dog slow, but I did a lot of development on it* and it happily traveled with me around the world and back and forth. It was so light I would often have to check my bag to see if I'd forgotten it. That happens very occasionally with my MBA as well, and is a reason I didn't upgrade to the 15-incher.

I think the ipad pro with the "magic keyboard" weighs more than a macbook air...?

* Note: I do all my development in Emacs, not a heavyweight development system and generally do the builds on a remote linux machine so the slowness of the machine wasn't the big deal for me that it might have been for others. But sometimes, if the network was slow, I compiled locally and it was still fast compared to the much older machines we used to use!