I know there were questions to whether or not airplanes would be flyable in V, and some of you are pretty certain that they will be, if I'm not mistaken. But I came across this on Rockstar as I was reading the Newswire about the screenshots. I'm assuming they're talking about V when referring to their "biggest open world game to date". And if they are, indeed, referring to V, I guess it's pretty much confirmed that airplanes will be flyable in V.
“Hey guys hope everything is good over there in Rockstar. Just a question referring to GTA 4, the game was brilliant and I really enjoyed and still do, but what disappointed me was the lack of planes and jets... Can you tell me why you didn't include them, I'm sure you have a very valid reason?” – via Mouthoff
The city was simply too small for effective and enjoyable flying. It was the first time we made a high definition open world, and it was a massive amount of work to make something on that scale – we simply could not make an environment big enough for planes to work properly. Fear not, they are returning in what is our biggest open world game to date.