More than 300 first class Qantas tickets worth more than £10,000 each were mistakenly sold at a discount of 85%.
The Australian airline blamed the error on a coding glitch on its website, making the mispriced tickets available for return travel to the US for eight hours last Thursday.
Qantas is to refund or downgrade passengers who were sold first class flights at a huge discount into business class.
More: Qantas resolves app privacy breach
Third European city gains Qantas direct Australia flights
Qantas agrees payouts after misleading customers over cancelled ‘phantom’ flights
A passenger travelling business class would still be paying 65% less than usual for their ticket, the airline said.
A Qantas spokesperson was quoted as saying: “Unfortunately, this is a case where the fare was actually too good to be true.
“As a gesture of goodwill, we’re rebooking customers in business class at no additional cost.
“Customers also have the option of a full refund.”
The airline’s terms and conditions state when customers book that if there is an error or mistake that is reasonably obvious in the fare price, the airline is entitled to cancel the booking and offer a full refund.