Why not take both?  It's a long flight back, too.

I like to travel as light as possible, and wouldnt feel so bad if I accidentally misplaced one handheld versus losing both.  the other thing is that I like to read while flying, and I think that one handheld will tide me over whenever I need a break from reading.

3DS with a Zelda title. 

I do have A Link Between Worlds already loaded onto my SD card for my 3DS.  I also have a physical copy of Ocarina of Time, and the GBC Zelda games...  So I think that I would be set no matter what in regards to Zelda.

I would pick the 3DS over the Vita.  If I had to take the Vita, I would bring Persona 4 Golden.  As for a game on the 3DS, there are too many great games to choose from.  Not only do you have plenty of 3DS games, you also have a crap load of DS games you can play too.  

I do only have 2 physical Vita releases at the moment, Persona 4 and FF X.  Now that I think about it, I find it interesting that they are both ports of PS2 games.

Well I only have a 3DS so the answer is obvious, but what if you had digital games on the 3DS or Vita? That way you wouldn't limit yourself to just one. But if it was me, Pokemon Y probably.

I do have plenty of digital games on both my 3DS and Vita.  The thing is that I have little desire to fumble around and possibly lose the physical games.  That is why I want to limit myself to one cartridge.

Atari Lynx.  California Games. 

one problem.  I would probably have to have a seperate suitcase just for batteries to keep the thing running.

i had that same thought!

I would take my 3DS if for no other reason than imagine all the street passes you'll get. Gamewise that's a tough one depending on what kind of games you enjoy. If your into RPG's for sure take Pokemon or Bravely Default. Now that I think about it maybe the Vita would be best just because you could buy games and instantly play them there. Since they are not region locked like the 3DSs. But dem street passes tho! AHH I don't know I'd take both. 

I was thinking about the streetpasses.  The only thing is that I don't actually know of any true benefit to street passing...  I know that there is the Bravely Default village thing, but I don't actually have that game so the street passes would do me little good.

Other than opening up puzzle pieces and being able to progress in the Mii games to get tickets to get hats for your Mii but if you're not into that. Then I say take your Vita instead and get some cool import games or the 64GB memory card while you are there.

3DS and since I have a 32 GB SD card I'd probably put Animal Crossing in the Slot because I have way more than 16 hours worth of games on the card. 

As for the Japan trip let's just say I hate you and leave it at that. LOL

I have 5 zelda games on my 3DS card, 4 MegaMan games, Bionic Commando, Virtues Last Reward, Shantae, Cave Story, Mole Mania, Simon's Quest, and some stuff that I dont remember.  I also have even more games on my Vita memory card...

Sorry to bring up the V word and if my sister was not in Japan at the moment, I would not be heading out there. 

While I do love my 3DS, I have to say that if I was going to stare at a sceen for a long time I'd choose Vita. 3DS small screen does give me blurry vision, and while you can say the same for VITA, my eyes suffer a bit less with VITA. So, Persona 4 or any FF PSOne classic on PSN would be my choice. Happy travels!

3DS with Fire Emblem and maybe a couple Virtual Console games saved to the memory card.

Me too. 3DS and Fire Emblem. Howlongtobeat.com says the main story takes 30 hours, so it'll fill the 16 time frame.

I'm actually leaving in the morning to do something traveling. My flights aren't near as long as yours but I'll still have plenty of down time. I'm taking my 3DS and not my Vita because the Vita is just so dang nice (not to mention expensive) that I'm afraid I'd lose or damage it during the trip. Of course, traveling with a not-quite-two-year-old, I'm not sure how many chances I'll get to play something lol.

Since I have neither console, I'm afraid I will be of little help to you. When I travel, I usually take my trusty DS Lite with me and Civilization Revolution. I love world domination on the go.

I have zero experience at present with the Vita, so be default I'm going to have to go with 3DS.  In that 3DS for the sixteen hour flight would be an RPG.  Probably a Legend Of Zelda game.

Because I only have a 3DS, the answer is obvious. For the games, I would say something that would make entertained for ours, like say Pokemon, and another pro would be the DS games.

Vita with Persona 4 Golden or FFX. Something long and heavily story driven to pass the time.

Since I don't own a Vita, I'm gonna go ahead and recommend the 3DS and either Fire Emblem or Pokemon.

The PS Vita is more comfortable in the hands, while the 3DS XL in my opinion just ain't that comfy enough. It really depends, not much of JRPG person either. PS Vita has PSone games, 3DS has NES games although I wish it had SNES and GBA.

I'd go with a Vita with a big memory card to DL lots of games on the system. it's what I did during my trip to the east coast. I know it's too late to say such but I'll be waiting to see what you went with upon your return.