The term UNITED RIVAL is composed of two crossword solutions, DELTA (5 letters) and TWA (3 letters). DELTA is an American airline founded in 1924 and based in Atlanta, Georgia. It is the world's second-largest airline in terms of passengers carried and fleet size. TWA, or Trans World Airlines, was an American airline founded in 1930 and based in Kansas City, Missouri. It ceased operations in 2001 after being acquired by American Airlines. Both DELTA and TWA were rivals in the airline industry for many years.