WASHINGTON (Reuters) - The U.S. Transportation Department has imposed a $2 million penalty on JetBlue Airways ( JBLU ) for operating four chronically delayed flights on domestic routes - the first time it has imposed such a fine on an airline for the prohibited scheduling practice.

USDOT said on Friday that as part of a consent agreement with the airline, JetBlue ( JBLU ) will pay a $1 million fine and the remainder will go to compensate customers affected by its chronic delays or any future disruptions within the next year.

As part of the settlement, JetBlue ( JBLU ) has agreed to provide vouchers worth a minimum of $75 for passengers for future flight cancellations or delays of three hours or more caused by the airline within the next year.

JetBlue ( JBLU ), which did not immediately comment, told USDOT it did not admit liability but agreed to settle to avoid the expense and uncertainty of litigation.

USDOT said at various points in 2022 and 2023 JetBlue ( JBLU ) operated chronically delayed flights between New York and Raleigh-Durham, Fort Lauderdale and Orlando along with a flight between Fort Lauderdale and Windsor Locks, Connecticut.

"Regardless of the cause of the delay (carrier, weather, national airspace, security) for any specific flight, JetBlue ( JBLU ) had adequate time to act to avoid the chronic delays," USDOT said.

The airline said it spent tens of millions of dollars to address issues with air traffic control especially in the U.S. Northeast corridor to as much as reasonably possible to prevent any chronic delays.

USDOT said there were 395 delays and cancellations across four chronically delayed flights in total, which meant U.S flights that are canceled or arrive more than 30 minutes late more than 50% of the time over a month.

USDOT estimates JetBlue ( JBLU ) was responsible for over 70% of the disruptions for the four chronically delayed flights.