On Thursday, some customer’s were able to book flights for only the cost of airport and security fees.
Air fares between cities such as Washington, DC and Hawaii were being sold on the site for $0 to $10.
Ticket prices on other domestic routes were displayed as $0, plus $5 tax.
“One of our filings today contained an error which resulted in certain fares being displayed as zero. We have corrected this error, ” said United in a statement Thursday.
“We’ve reviewed the error that occurred yesterday and based on these specific circumstances, we will honor the tickets,” the company tweeted Friday.
CNN contributed to this report.