I've always been fascinated by Russian history — who wouldn't be, right? It's the land that ate Nazism!
So putting a giant tome on Russian history into my carry-on luggage makes sense, right?
Also, those two novels I've not yet finished. And that magazine with loads of massive features, and I better take a notebook so I can make — er, notes — to speed up completion of my novel ... in fact, I'd best make room for the laptop, in case inspiration strikes and I finish writing the novel.
There's something about long-haul travel that always makes me overestimate my capacity for time-filling intellectual endeavour. Once I'm on board, a well-thumbed inflight magazine, a movie and a couple of glasses of red is all the time-filler I need.