>who the fuck is the masketta man?
Barsad. Is that his real name? First name? Last? We don't know. What's important is that he is Bane's first lieutenant and most trusted warrior. Is he loyal? We don't know. ARG elements for the movie from December 2011 imply that he might be Georgian. He's also an expert marksman. He most likely faked his death since that part where he slips is kind of unconvincing. That's all we know.
>why does this strange guy with the strange accent refers to bane as the masketta man?.
He said "masked man". The "etta" part comes from the gun-clicking noise we hear in the background. He was referring to Bane, as in explaining why CIA asked why Bane wears the mask and later showing that he in deed has a mask, thus he is the famous masked man.
>why does he wear the mask?
If you pulled it off, he would be in extreme pain since he suffered a terrible injury to his spinal chord and his face in the past. Pain-killing medication runs through the tubes in the mask into his lungs, explaining why he breathes so often. At the end, when his mask is hit, the tubes come apart and hissing noises are heard. This is the gaseous medicine escaping and bringing back the pain.
>who the fuck is CIA
"Bill Wilson" is a CIA operative (they like it when you call them officers) who just happened to be the one the Agency picked to pick up Dr. Pavel from Uzbekistan in order to take him to America, most likely for torture questioning.
>does he survives after the plane crash?
Maybe. Evidence to the "yes" answer are that he has some kind of parachute in his jacket pocket (see: Parachute Theory) and that when he is lying down when last seen, he is clearly 'playing dead', so that the guys don't shoot him before throwing him out of a plane.
>why did bane needed dr pavel's blood?
The most widely recognized theory is that it was to fake his death, having his blood (and thus DNA) present in the plane so that anyone looking for Pavel would assume him dead on account of this. Perhaps he also needed a transfusion to make sure this was the Pavel they were looking for, perhaps he was using it as a scare tactic, or maybe he was insulting the intelligence/technology of the Russians in their methods of determining whether Pavel was dead or not.
>isn't dr pavel's identical to one of the mafia guys from the second movies?
No.
>why did one of bane guys "sacrifice" himself by letting bane crash the plane with him on it?
Bane told him to stay even though he earlier caught CIA's bluff that the flight plan listed one of them, as it didn't. Why did he do it anyway? Perhaps it was either to make outsiders think that it was an intruder aboard that caused the crash (which only makes sense if Bane was trying to get a story out of the Zionist media) or to get revenge on the brother for something personal. Either way, he stayed because he was following a blind precedence or think he was dying a martyr in order to rise the fire but he really wasn't, and Bane knew this, shown in how sarcastically he says "Yes, the fire rises!"
>what was the point of shooting somebody before dropping them of a plane?
Well, first of all, it was a ruse to scare the detainees, but if he actually did it, than it would be to ensure that they're dead and that tossing them out into the country makes it seem like they were killed by someone randomly and their bodies left. Clean disposal.