AIRLINES

Air Fare Battle Intensifies: United Air Lines parent UAL Corp., Trans World Airlines Inc., Continental Airlines Inc., Northwest Airlines Corp. and USAir Group Inc. all lowered fares for winter and spring travel in the United States, Europe, the Caribbean and Mexico, matching discounts announced by America West Airlines Inc. and AMR Corp., parent of American Airlines. American’s discounts range between 35% and 40% in the contiguous United States and up to 25% for Europe, 30% for Mexico and 29% for Caribbean destinations. There are purchase restrictions.