Doug and Ruth Eaton have long planned a dream vacation to Europe.
"We're taking a two week cruise on the Rhine," Ruth said.
The couple also planned to upgrade their coach seats to business or first class using points they had earned on their United Airlines Mileage Plus credit card.
"I'm not the most petite person in the world and I don't fit very well in coach and this was a way to do that without having to buy it," Doug said.
The couple says they have used their United miles to upgrade many times over the past 10 years. However, this time, their miles just didn't fly.
"United was now going to charge us $1,600 to use our miles," Doug said.
It turns out United now charges a co-payment, along with miles, to upgrade from most economy class seats. Unbeknownst to the Eatons, United started charging the fees last year and they would have to fork over a co-payment right at the gate.
"They were charging me to use the rewards that I had earned over the years and I was flabbergasted," Doug said.
The co-pay did not show up on their itinerary. United lists the fare at $1,700 apiece in business class, with no mention of the extra charge.
"We have done this in the past, several times, and we've never paid a cent," Doug said.
It was their travel agent who warned the airline would collect the fee at the gate -- $425 per passenger each way.
Travel attorney Al Anolik likens the copayment to other new airline fees for services like checked bags, meals, even pillows.
"The consumer doesn't know it; they've worked towards getting their mileage, they show up and all of a sudden a new word for the day, 'co-pay,'" Anolik said.
United isn't the only airline with co-pays. Continental and American charge fees with miles to upgrade many economy seats, so does U.S. Airways on international flights.
The Eatons contacted 7 On Your Side and we contacted United. It said the co-pays give more passengers access to premium seats since more low fares now qualify for upgrades. It takes fewer miles to upgrade, though there is the co-pay.
However, United said the fee came as a surprise to the Eatons and, "as a gesture of goodwill we have waived the co-pay for their return flight,'' saving them $850 in all.
"It was wonderful because United wouldn't have done anything without 7 On Your Side," Ruth said.
United says passengers shouldn't be surprised when the airline demands a co-pay at the gate. Customers are told about the fee when they book directly with United. The airline says the fee isn't collected until departure in case customers decide not to upgrade or if they switch flights.