727, for some reason...
Years ago, we got diverted on a cross country flight and landed at Boeing Field due to weather at the destination airport. We had to de-plane using the built-in stairway in the tail of the 727. To me, cool. I remember the stairway area was painted some sort of aluminum protective green paint, very "industrial". You could see the hydraulic lines in that area. Then as we left the plane, I remember looking back over the fuselage and thinking, WOW, we just crossed the entire country in that machine... As an engineer, it was a moment to remember. Not like the sterile leaving of an airplane through a standard "jetway". That's just like going from one building to another.