Some of them were a one-off type of experience (I was travelling somewhere and the cabin was full...this was easier to do pre-9/11 but is still possible) and some of them were required for my job (under federal regulations, aircraft dispatchers are required to ride up front 5 hours per year on their own company's aircraft for operational familiarization.) For those of you new to my blog, or who are just curious about what I do for a living, an excellent article on the subject (which I have referenced before) can be found here.
Here are the planes I've ridden in the cockpit on my "required" trips:
Saab 340 and Dash 8 (both turboprops)
Avro RJ-70, Fokker 70, Canadair RJ, and BAE-146 (regional jets)
Boeing 737 and 757 (I'm sure most everyone has heard of these.)
On my "fun" trips to get somewhere (or get back from somewhere), I've ridden up front on the Airbus A320, as well as a Boeing 777 (on my last trip to England, that was how I got there) and a Boeing 747-400.
Jumpseating is an option most commonly used by pilots when they are commuting to or from their "hub" where they fly out of. In popular culture, "Catch Me If You Can" showed Leonardo DiCaprio's character, Frank Abignale, impersonating an airline pilot and travelling all over the country jump seating. Due to post-9/11 security procedures now in place, this would be very difficult to pull off today.
Many pilots are unaware dispatchers can ride in the jumpseat, which I always find annoying. I used to jumpseat a lot on Southwest when I lived in Las Vegas, and after a couple of incidents, I got to know exactly which paragraph in their flight operations manual said that dispatchers from other airlines were allowed to ride in their jumpseat. Still, since there are only a few thousand dispatchers in the US, versus tens of thousands of pilots, so I guess it's understandable.
Riding in a cockpit jumpseat is exciting initially, and it's a great view, but the novelty wears off fairly quickly. After that, it's usually just a way to get somewhere. I always do try to learn something from the flight crews I'm travelling with, though.
Wow, this turned into a semi-decent post, once I got going! To top it off, I will add a picture of me in the cockpit taken by a friendly pilot when I got to ride up front on the 747. I apologize for the crappy picture quality, since the camera was using a flash and the picture is too bright...but this is about the only photographic evidence I have that I really have ridden up front before. I'll try and take some better pictures next year.