Jet fuel rose from just over $2 a gallon in January to $4.50 by September 21, prompting airlines to trim midday and midweek routes. Delta has since cut its full-year outlook, absorbing $6 billion in higher fuel expense, and CEO Ed Bastian warns fares will rise if fuel stays high. European airlines have lost about five points of through traffic via the Middle East, with Turkish and British carriers cutting flights, and Ryanair's O'Leary says European fares could rise 10% to 20% next year on fuel costs tied to the Iran war. Hopper data shows Thanksgiving round-trips up 31% and Christmas tickets up 23% from last year.