Is it possible to bluff one's way to the flightdeck like in Catch Me If You Can? I was watching some clips from Catch Me If You Can starring Leonardo DeCaprio as Frank Abagnale.

I was wondering- If brought a ticket on an airline today, came dressed up like a pilot, would you, be able to sit in the cockpit? (assuming pilots are normally allowed to jumpseat in that jurisdiction) Say you come onboard the plane and present them a fake ID at the door. Is there anything to prevent this from happening, or are we still as vulnerable to this type of trick like in the movie?
A lot has changed since the Frank Abagnale / "Catch Me If You Can" days, and riding as a non-revenue passenger (particularly in the cockpit jump seat) is no longer not as simple as grabbing a passable captain's uniform, polishing your shoes up, and smooth-talking the flight crew.  

Someone seeking a ride in an airplane jump seat would still have to pass through airport security and prove their identity &amp; authorization to occupy such a seat to the satisfaction of the crew operating the flight, which would likely include checking credentials that are at lease somewhat difficult to forge.

So in short it's possible – if someone is particularly adept at social engineering, forgery, and has at least a working knowledge of airport &amp; airline security procedures they might get away with it – but it's extremely unlikely, and as has been pointed out the consequences if and when you get caught are particularly unpleasant these days.