(NEW YORK) -- When Brian Kelly's intern called to alert him to chatter on FlyerTalk, a popular frequent-flier website, about an extraordinary airfare deal to Asia from United Airlines, Kelly jumped on it and booked a first-class, round-trip ticket from New York to Hong Kong. Total cost? Four frequent flier miles and $43.
Kelly, a travel expert who runs a website called The Points Guy, is no stranger to "error fares," as they're called in the industry. Typically, an error fare will leave off a zero on the price, or something similar. But Kelly said errors on rewards tickets are far more unusual.
"I've never seen anything like it," he said. "I priced out several different routes and it [the rate] was available, not only to Hong Kong but to Beijing and Shanghai."
In recent years, error fares have frequently not been honored by the airlines. But new Department of Transportation (DOT) rules state: "A purchase occurs when the full amount agreed upon has been paid by the consumer. Therefore, if a consumer purchases a fare and that consumer receives confirmation (such as a confirmation email and/or the purchase appears on their credit card statement or online account summary) of their purchase, then the seller of air transportation cannot increase the price of that air transportation to that consumer, even when the fare is a 'mistake.'"
Kelly said he received a confirmation email within 15 minutes of purchasing his ticket. Still, United said it is not going to honor the tickets.
In a statement to ABC News, the airline said, "Over the weekend, we discovered a programming error that allowed customers using united.com to obtain Mileage Plus travel awards to and from Hong Kong for as little as four miles roundtrip per person, substantially below published levels, which we disclose to customers. We have since corrected the error and will be in contact with customers who have tickets issued at the incorrect award amounts. Customers will be given the choice to redeem at the correct mileage amount or re-deposit their award with all fees waived."
A DOT representative said they're looking into a number of complaints received about United's rescinding the frequent-flier tickets.
"Our rule on post-purchase price increases applies to frequent flier tickets, particularly when they also entail cash payments," the spokesperson said.
Kelly said he still hasn't heard from United regarding his ticket and he still holds his confirmation.
"Reasonable people realize this was a mistake," he said. "Even so, it will be interesting to see how the new DOT rules play out."
Copyright 2012 ABC News Radio