Porter Airlines has cancelled all remaining flights Friday departing from the Billy Bishop airport in Toronto's downtown as the city is blanketed with fog and hit with a freezing rain warning.
Porter spokesman Brad Cicero said the problem is poor visibility and that more flights will be added Saturday.
Pearson International Airport also has dozens of delays and several cancellations.
CBC meteorologist Michelle Leslie said the worst of the weather will come between 6 p.m. and 10 p.m.
"This is not a major ice storm, but watch your drive," she said, warning motorists to be particularly careful on bridges and overpasses.
Environment Canada warned in the early afternoon Friday that freezing rain was moving from lower Michigan to Southern Ontario, with a freezing rain warning in place from the Bruce Peninsula to Brockville.
It said the freezing rain would hit Toronto around the supper hour and spread northeastward by late evening, with amounts between three to six millimetres.
The freezing rain will taper to patchy drizzle or freezing drizzle early Saturday, the weather service said.