SPIRIT AIRLINES, said to be the 14th largest US carrier, based at Fort Lauderdale, Florida,with a fleet of 32 MD 80 aircraft, has taken the unusual step of announcing an initial order for 35 Airbus A320 series aircraft (which could go to 95), which has not been actually confirmed by the Toulouse-based manufacturer. The Rolls-Royce IAE 2500 engine appears to be the lead engine in preference to the CFM 56. Last month, Spirit Airlines sold a controlling stake in the company to a Los Angeles venture capital fund for USD125m. At the time the company said it wanted to use the proceeds to double its fleet over the next five years.