"It was $5 round-trip, no fees, nothing," she said. "This is nuts."
She checked in right away and printed her boarding pass hoping to increase her chances of being able to use the ticket.
Leahy said a co-worker scored a cheap flight to San Francisco while another got one to DC for later this year.
On one day in 2008, United accidentally dropped a fuel surcharge that ran as high as $130. It honored the tickets sold without the surcharge.
Today, Social media such as Twitter ensures that word of mistake fares spreads even faster than before.