Heavy fog is playing havoc with flights in and out of St. John's International Airport.

On Friday evening, many flights were delayed or cancelled.

Wayde Guinchard was frustrated with the changes to his travel plans. He was due to fly to Toronto on Friday afternoon for weekend meetings.

"I was scheduled originally for [Saturday] morning, but because I had earlier meetings, I had tried to change it to [Friday]," he said.

"But now I'm out of luck for [Saturday]."

Guinchard said all of his airline's flights for the rest of the weekend were booked, and his first chance to fly out will be Monday morning.

He said he may try to get a flight with a different airline.  

Cathy Wentzell was also scheduled to leave Friday afternoon. She said the flight left Halifax, but it wasn't able to land in St. John's.

She said she's been rebooked for a flight on Sunday evening.

"Which is not so good, because I'm supposed to go from Ottawa, back to Moncton on Monday morning. So it's going to be a little tight for me," she said.

But Wentzell said she accepts the delays, because it's all part of winter travel.

Trevor Wheeler has been trying to get back to Fort McMurray since Thursday, but his flights keep getting cancelled.

While he's late getting back for work, Wheeler said he can't change the situation.

"You can't really help nature," he said. "It's no good to get upset over it."