Can a passenger request to visit the cockpit during a flight? As a kid, I remember going to the cockpit of a plane with my mom (I believe the airline was AOM French Airlines).

Is this still possible now?

I understand the answer might differ with different airlines/countries, I'm mostly interested in European and Asian airlines/countries, specifically Japanese.

Is there some specific regulations for international flights, or does it depends on departure/arrival locations?
This stopped after the World Trade Center attacks.

You might be able to get a kid in briefly before the plane takes off.