Hamilton was one of only two listed by Statistics Canada that had higher cargo tonnage in 2020 than 2019, an increase of more than 24% (Winnipeg was the other, with 2.7% more total cargo). Cargo flights were up 20% at YHM as well.
Cargo shipped in the holds of passenger planes must have really dipped at most other airports, due to the drop in passenger flights... 60-70% fewer of those flights at major airports.
Cargo data:
https://www150.statcan.gc.ca/t1/tbl1...pid=2310025401
Passenger flight data:
https://www150.statcan.gc.ca/t1/tbl1...pid=2310025301