JetBlue argues that Mint, the carrier's version of business class, has driven a 50 percent decline in premium fares on some competing U.S. routes. It believes it can drive a similar reduction for premium travel between the United States and Europe. Separately on Thursday, JetBlue announced a biometric self-boarding gate for international flights at New York's John F. Kennedy International Airport (JFK), becoming the first domestic airline to launch the use of facial recognition technology to verify passengers with a quick photo capture for international travel. JetBlue has 14 million annual JFK customers. (Reporting by Tracy Rucinski; Editing by Leslie Adler)