I had a memorable cockpit visit on a Qantas Boeing 707 in 1977 from Jakarta to Sydney. We had just completed a school tour of Indonesia and were returning home from the old Halim airport in Jakarta. There must have been about 15 of us asking to visit upfront and the crew were fantastic in accommodating all of us, not at all the same time of course!
A few years earlier, we were also on a Qantas 707 flying from Kuala Lumpur to Sydney. I must have been about 9 years old at the time and weather got a little bumpy so the flight engineer strapped me in the jump seat. I ended up being in the cockpit for about an hour due to that. Sadly, those days are long gone.