One of my greatest memories from childhood (late 1970s) was when my parents somehow wrangled an unofficial behind-the-scenes tour of Heathrow. We were shown around a number of hangers with various planes in. We were able to go on board the planes, as well as walk around under them.
The last plane we were shown was a BA Concorde that was being cleaned up and serviced between flights. We walked under it, then climber the surrounding gantry and went on board.
Because of maintenance work being carried out, the nose wheel was retracted and we were told that we could go into the cockpit and take a seat at the controls, but only two of us allowed in at a time in case the plane tipped up and caused damage.
After that we went out on the gantry around the Concorde and the best bit was we were able to stand right in front of the plane and look in the cockpit windows. Then I reached out and shook the Concorde by the nose. Awesome!
A pity I've never flown on one, or even seen one fly. Just plenty on the ground,