[masonic]

  I remember that on one flight you could just walk to the front, and watch the pilots fly the plane through the open cockpit door

That changed in the USA even before 2001, at least by typical policy if not statute.

I recall a trip in the late 1990s flying Aur Canada (maybe YYZ-SFO) and while in Canadian airspace, I was invited in right behind the copilot to hang out for 20 minutes or so. I was surprised how much air traffic could be seen just with the naked eye.