A former Southwest Airlines employee and her husband pleaded guilty Tuesday to wire fraud, acknowledging they stole more than 5,000 plane tickets and sold them to friends, co-workers and other acquaintances.

Althea Jackson acknowledged acquiring about 5,600 courtesy airline tickets when she worked at Southwest from 2001 to 2005, U.S. Attorney Johnny Sutton said.

The tickets are normally given to inconvenienced passengers and vendors or to passengers who assist flight crews, such as by providing medical assistance during a flight.

Jackson and her husband, former Bexar County court bailiff James Jackson, then sold the tickets below market value, with many going to "friends, relatives, acquaintances and James Jackson's co-workers at the Bexar County Justice Center," Sutton said.

Prosecutors said the defendants sold them for cash from 2000 to 2003. Prosecutors estimate the scam was worth as much as about $1.8 million, a figure the couple's attorney, Jay Norton, disputes.

The two each face as many as 20 years in prison and $250,000 in fines but will likely get two to 2 1/2 years in prison and a reduced fine under the plea agreement, Norton said.

Sentencing is set for May, according to the U.S. attorney's office.