My husband. If he’s not an option, one of my siblings or cousins.
That’s it.
Are you sure? Because:
I bet Miles Vorkosigan would be a great choice! Lots of stories, and small, not taking up much space. On second thought though, he’s pretty darn hyper (less as he ages) and being stuck for 15 hours with him could easily be too much of a good thing!
Exactly. Besides, some of the best stories are undoubtedly classified.
Remember- nothing in the OP stipulates that your seatmate is obligated to entertain you.
True, but Miles sitting still for 15 hours and not talking is a low to zero probability. 
Of course, given his luck and ability to attract problems (shared with many other fictional characters) I would worry about the plane being hijacked, crash, start running out of fuel, being involved in international (interstellar) politics, or weirder things yet!
In fact, most fictional characters sufficiently interesting to merit a mention here would be a similar risk. And whatever you do, don’t book a ticket next to Elric of Melniboné or Roland Deschain of Gilead.
I would rule out anyone with the initials “L.L”.
From Lois Lane to Lazarus Long, they are all trouble magnets.
Eric Ross Weinstein
Those of you who prefer not to exchange a word with the stranger beside you are missing out! I’ve had some of the most interesting conversations of my life with random seatmates on planes and trains.
One in particular was a Finnish university professor who studied the evidence of old and vanished Finnic languages across northern Russia in the form of “hydronyms” (names of rivers and lakes), as well as similar evidence of an old unattested pre-Finnish language in Finland.
I concur.
One of my favorites was a young Australian women who sat next to me and we had hours of interesting conversation from Frankfurt to Chicago. She was really into sailing and told me about these amazingly long sails she took in various parts of the world, and we really hit it off. I even got her phone number! However, almost all the way at the end of the conversation I found out she was … 16? Ah! (I was 21 at the time.) I would never have guessed, especially with all the life experience she had had. Oh well. (I never did call her.)
My fatger always ended up next to friendly, chatty people willing to tell him their life stories. I get stuck next to some grump who hasn’t said anything friendly to a stranger since about 1962.
Sitting next to the same stranger for 2000 miles on the train (two days) can be challenging either way. More often, I end up next to someone who is not at all interested in conversation (but almost always an empty seat eventually becomes available), which is very uncomfortable. But sometimes I get a chatty person: two days of nearly constant conversation is exhausting.
I listen to far too many WWII Pacific War podcasts and lectures.
There are a couple of historians that I would love to ask a zillion questions and hear more about their thoughts.
Of course, they may not appreciate it as much as I would.
you probably have seen the interview he did on Rick Beato’s channel a few weeks ago … (if not, a quality hour’s time to spend)
and yes, he is one heck of a guy, fast, smart, eloquent, read … - the kind of person I have no doubt would have done well in life if he never picked up drumsticks or so …
Lucy Lawless might be all right.
In her previous series enemies attacked nonstop, and in her current one she is surrounded by murderers.
The important thing is that he just takes the tip.
Honestly, the best seat mate I’ve ever had on a flight is my wife.