i really think the keypad in the tunnel leads into the mountain (if you can even get inside)
someone hack or something and search if there's even a cave or something in the mountain so we stop wasting our time
Personally, I think that is the single best argument to how there is probably no jetpack, or in depthreward to this goose chase. The game files are out there, people are even digging up stuff that might suggest that there will be some sort of micro transaction for the online. If there was a jetpack somebody will come across that game file. Its a vehicle and in code form its probably not hidden at all. At the very least it would probably be easier to find it in code form than it is to find it in game.
Don't think so... The code is not that simple to read, if rockstar named the jetpack Randomstuff_9952 noone will find it. And btw there is at least 2 UFO's with psysical existence and it wasn't spotted with the code but with the people looking for them ingame.
I only slightly know the coding from GTAIV modding. I can't imagine it differs too much here, but if it did it shouldn't be too hard to find. I also,cannot say that I know if anybody has looked for the UFOs in the codding. So you might be right. Although, if they cannot be piloted then that would mean that they wouldn't be in the same place if you were looking for vehicles. The jetpack on the otherhand would be and it would be with the same files that all cars/planes/helicopters are. I'm sure its not easy enough for just anybody to crack open and check it out but its a little more absolute than chasing the imaginations of hundreds of people.
I'll be fair I don't mind chasing all these conspiracy theories (well some of them.) but the code doesn't lie, and the code is out there so anybody with enough knowhow could settle this in a few hours let alone a few days. I have to imagine that with all the prying eyes we have on the game files at least one person would have cracked that nut by now.