By luck, someone just posted this on YouTube, which shows exactly what I'm saying in the first couple of minutes:
I'm the same height as you (and quite slim), so I guess I must fly on cheaper airlines with smaller seats! TBH, there is a lot of variability in airlines. Long-haul flights are generally better, but the inter-state flights where I live are often quite small (some are even 50 seat turbo-prop aircraft to smaller cities).
The big problem is if someone reclines their seat. Probably even a 13" ultrabook would become uncomfortable because it would end up so close to your body (you have to slide to tray towards your body to allow the screen to open wide enough to see the screen).