Rob Eedson of Ottawa figured he'd spring for a small upgrade when he purchased Air Canada tickets for a week-long family trip to San Diego in October.

He bought the tickets online and paid extra for three "economy flex" fares — for himself, his wife and four-year-old son — because they included one checked bag per passenger on the outbound and return flights.

The tickets were on a "codeshare" flight — meaning an airline is selling seats operated by a different carrier. In this case, Air Canada sold the tickets but the Eedsons were travelling on United Airlines.

When they showed up at the United check-in counter, an agent insisted on charging for luggage — again — $40 per bag, despite Eedson showing him an Air Canada receipt for three checked bags.

On their return flights, a United agent charged the family for baggage again.

Even before flying home, Eedson submitted a claim to Air Canada to be reimbursed for the extra luggage costs, but it was denied.

But that response violates baggage rules, laid down by the Canadian Transportation Agency (CTA), for flights to and from Canada when passengers have a ticket that involves more than one airline.

An Air Canada spokesperson declined to answer most of Go Public's questions about Eedson's case, but wrote that the airline's policy is "to abide by all applicable laws and regulations."