Braniff Inc. said it will acquire Florida Express Inc. The Dallas-based carrier said it plans to complete the deal in January, when it will merge the two operations. Braniff said it would use its fleet of 25 Boeing 727s and 10 recently acquired Boeing 737s to link its routes with those of Florida Express and to expand into a number of new markets, mostly on the East Coast. Florida Express, based in Orlando, has 19 BAC 1-11 jets. Terms call for Braniff to exchange 1/6 of a share of its common stock and one share of a new series of cumulative convertible preferred stock for each of Florida Express' 7.5 million common shares outstanding.