On an upcoming trip I'm actually going to give an iPad with magnetic keyboard I bought a couple years back, assuming different travel patterns than I've had, a try. It seems to work fine. An iPad is also great for plane/train entertainment without a keyboard. But, honestly, it's no lighter than a MacBook Air would be and if my ancient MacBook Pro dies--have a newer one up in my office--that's what I'll probably buy.

I have traveled with just my iPhone and can get by but don't really love it.