I say the MacBook will best suit your needs. It is light weight, powerful enough for what you want to do, has good battery life. I also suggest looking at the refurbs available from Apple. Some really good deals available right now. They are like new or better, carry the same warranty, can have AppleCare added and you can save a couple hundreds dollars.
Three things are stopping me from buying the MacBook Air: The non retina screen, clunky bezels and very bad speakers, and I spend most of my time watching YouTube videos so speakers really matter to me
My boss has passed his MacBook to me and I love it! The Retina screen really does make a difference and the 2016 model is definitely snappier when it comes to open ping documents. It is perhaps the most beautifully engineered device that Apple has made. I only type word docs and and look at a few spreadsheets so it is more than suitable for my needs. I would also recommend the entry level model - you can always take it back if you think you need more.