I used a ZED fare on Lufthansa through my company (spirit) and it worked very well. Just as stated earlier, standby obviously. At spirit I was only able to buy a coach ZED, but the gate agents hooked me up with an empty row to myself. I introduced myself to the flight crew, but no upgrade. I had a seat so not expecting more. Happy to ride. Your carrier may offer a first class ZED if it is that important to you. The fare was cheap, $290 DTW-FRA-PRG roundtrip. Lufthansa was great to me throughout the flight. I've heard that sometimes foreign carriers will let you in the jumpseat if flight full....don't count on it however. Also, changing planes in FRA, the coach was full, FC empty. They moved revenue pax to first so I could get on. They were very strict about who travels in first. Again, all I need is a seat so I'm not complaining. It is just a little different than the US.
While in Europe, I purchased a ticket on a major foreign carrier to fly around while I was there. I talked to the crew and they actually let me in the flight deck jumpseat to hang out with the crew during flight. Very interesting! Again, it's all up to the crew over there.
I've never riden the NWA Jumpseat overseas, but did fly on DAL, MaxJet and UAL overseas. They were all very accomodating, upgraded to First every time. I understand you must be dressed in at least business casual to be upgraded, however since we are all professionals this shouldn't be an issue. The US carriers will take great care of you while jumpseating. The crew did mention that due to TSA rules there are no offline j/s allowed in flight deck for international flights. So you will need a seat in the back open.
Taxes vary depending on the airport you are flying out of. UAL did not charge taxes out of ORD, but MaxJet charged $15 out of JFK. Not bad for a first class seat to London!
Over in Frankfurt on DAL, taxes were $85. Out of Stanstead on MaxJet was $35 pounds...so about $70 US.
It works great. Living in DTW, I'll take Lufthansa on ZED again for the convience.
hope it helps