Northern Canadians who connect through Edmonton to fly to and from anywhere else in southern Canada have noticed a hidden airport fee they shouldn't have to pay.

The Edmonton International Airport automatically tacks on a $15 airport improvement fee onto the price of airline tickets that appear as though passengers are making Edmonton their final destination.

That is an extra cost for travellers from the Northwest Territories who are switching airlines in Edmonton.

"Passengers connecting within four hours of their domestic or U.S. flight, or 24 hours for international flights, don't have to pay," Traci Bednard, a spokesperson for Edmonton Airports, told CBC News on Thursday.

Bednard said the airlines collect the fee on the airport's behalf when people book their flights.

Connecting passengers who are charged the airport fee can have it refunded, but it's up to them to get that money back, Bednard said.

"They can apply to Edmonton Airports," she said.

"We don't need a lot of information. All we need to see is just the itinerary and the flight schedules. In that way, we can refund them the airport improvement fee."

Yellowknife resident Turk Chan, who frequently flies to Vancouver with his wife and son — often connecting through Edmonton — told CBC News he noticed the airport improvement fee when he took a closer look at his airline receipts.

Chan said he's applied to get the fee refunded but that he's frustrated with the process.

"I have to go through the airport authority to get the money back and do a lot of paperwork for something I don't have to pay in the first place," he said.

Edmonton Airports collected $40.5 million through the airport improvement fee in 2008. The authority plans to raise the fee from $15 to $20 in September.