Most of my flights were in coach, and that should add 50% more to the length from biz and 100% more for international first class, especially if you get an inside seat. Even worse was the flight in the middle seat with an obese guy next to me that couldn’t get the arm rest all the way down.
Another fun flight was from Tokyo to some American city with a bulkhead seat. While do you don’t have anyone reclining into you, you also don’t have anywhere to put your feet.
For five years in the last 90s, I worked for an import company and attended countless trade shows in America and Europe (oh, my longest flight was actually from Orlando to Tokyo, 16 hours 40 minutes, and I did that three or four times). I was puddlejumping three to five time a year.
From 2000 to 2010 I worked for the Tokyo branch office of a US company and also went to many tradeshows as well back to HQ, then once a year to visit family with all the mileage I was accumulating. I had my own company for a while after that, and drastically cut down the travel.
A couple of the trips for the first company were biz class, but almost all were economy. Those years were hell.
Fortunately, the US company allowed my level of management biz class.
As others have pointed out, having lots of connecting flights is not great. When I take my family back to the States now, we are three to four hours to the airport by ground transportation, then a flight to either Tokyo or Seoul, then usually another connection in America, putting us 24 or more hours door to door. The first time we tried to save money and stayed overnight in the Seoul airport because they have a “sleeping lounge.” Insane. I was ready to kill anyone to looked at me wrong by the time I got to my mother’s home.
The best international flight I had was a Singapore Airline return from the Orlando to Tokyo. I had biz class tickets, but they selected me to fill out a customer survey on the Tokyo to Orlando flight. I don’t know if that was the reason, but they gave me first class on the way back. The seats go completely flat with your own little compartment and I slept like a baby on the way back.