The Fort Lauderdale-based carrier is to begin taking delivery of the A321s and A319s in March next year, replacing its fleet of MD-80 planes, said Spirit Airlines chairman and chief executive Jacob Schorr on Friday.
It also took an option to buy another 60 planes, bringing the total book value of the order to $5 billion, he said.
"The firm commitment for 35 aircraft, valued at approximately $2 billion, will allow us to accelerate our significant growth plans and more than double our size," Schorr said.
Spirit chose the Airbus aircraft because of the wider cabins and fuel efficiency, he said.
The carrier selected International Aero Engines' V2500 engines to power the aircraft, he said.
"IAE V2500 engines were chosen for their superior fuel efficiency which Spirit feels will become an ever increasing factor in maintaining its low cost structure," Schorr said.
IAE's shareholders are Pratt and Whitney, Rolls-Royce, the Japanese Aero Engines Corporation and MTU Aero Engines.
The carrier, which three weeks ago secured a $125 million investment from a group of investors led by Oaktree Capital Management, planned to announce growth plans, he said, without elaborating.
The agreement included a deal with International Lease Finance Corporation, Schorr said.