B.C. Premier Christy Clark's office is defending her travel expenses after documents obtained by freelance journalist Bob Mackin show she spent more than half a million dollars on private planes over the past five years. 

Many of the flights were between Clark's riding in Kelowna, in the B.C. Interior, and her home in Vancouver. 

WestJet and Air Canada frequently fly between those locations.

The premier's office told CBC News in a statement that commercial flights are booked when available, but added that "because of the demands on her time, we do charter flights when necessary as long as the per passenger cost is as close to commercial rates as possible."

B.C. Opposition house leader Mike Farnworth says that money is better spent elsewhere. 

"That's just the wrong priorities. That sends the message of someone who's out of touch with the realities of everyday British Columbians," he said. 

Farnworth says the Opposition plans to raise the issue in question period next week. 

Political observers say while the news isn't good for the premier, it's also far from fatal.

"A little more transparency could be in order in Victoria. But the fact of the matter is this is a popular premier, an effective and competent premier," said UBC political science professor Max Cameron. 

"Until there's a kind of credible alternative, what can do any real damage to her politically?"