Former JetBlue gate agent Tiffany Jenkins, 31, pleaded guilty in a Boston federal court Friday to three counts of wire fraud after upgrading the plane tickets of friends, family and acquaintances over the course of roughly 15 months. The scam, according to reporting by the Boston Globe, cost JetBlue approximately $785,000.

From roughly July 2016 through September 2017, Jenkins accessed the JetBlue reservation database to convert low-cost plane tickets into more expensive ones for more than 100 people. One example cited by Travel + Leisure involved reservations for a quick, inexpensive flight from Las Vegas to Long Beach, California, being switched to a more expensive long-haul somewhere else.

“As a gate agent, Jenkins had access to the airline’s computer reservation database and had the ability to use a special code, referred to as an involuntary exchange or ‘INVOL,’ to change flights for customers at no additional cost,” U.S. Attorney Andrew Lelling said in a statement. “This code enables agents to change flights for customers who miss their flights or experience a death in the family.”

JetBlue did not immediately respond to a request for comment.

Jenkins was arrested in November 2018 after carrying out 505 ticket exchanges. She faces the possibility of prison time and steep fines when she is sentenced in January.

“The charge of wire fraud provides for a sentence of up to 20 years in prison, three years of supervised release and a fine of $250,000 or twice the gross loss or gain, whichever is greater,” Lelling said.

Jenkins isn’t the first airline employee to use her position to obtain tickets fraudulently. In 2010, United Airlines staffer Mercedes B. Stafford was sentenced to 30 months in prison for fraudulently booking more than 525 plane tickets for friends, family and associates from May 2007 and October 2009. And this past March, the Chicago Tribune reported, United fired 35 employees for selling their “buddy passes,” which are meant to allow their friends and family members to fly standby at reduced rates.

Fraud, whether committed by employees or by regular passengers, weighs heavily on the aviation industry. According to the International Air Transport Association, credit-card fraud alone costs airlines nearly $1 billion per year.