While virtually all my BRU and LHR flights have been very busy in J, on several MXP segments there have been about 5 J pax in a 30 seat cabin! I have also done two MXP flights where I was the only J pax onboard!

Out of the NA routes, YYZ I have seen can often have lower J loads. Every time I have managed to get an empty seat next to me (in the 18 J cabin) and also seen several other empty seats strewn around. Sample size of about 10 flights in the past couple of years.