11" is small enough to use in coach
I have tried it several times. Of course easier in J. I don't know about 13".
If I was going to buy a 13" screen I'd get the Pro. For ease of weight and travel stick with 11". Scrolling isn't a big deal to me. If you really anticipate heavy computing use the above suggestion for a 13-15" Pro and an iPad (16GB wifi). You won't be disappointed.
John