Low-cost airline, EasyJet, firmed up on Thursday a contract for 135 Airbus A320 family of aircraft, potentially worth over USD 13 billion, according to catalogue prices. Airbus said in a statement that the shareholder\'s at the low-cost carrier had given approval to pursue the purchase of 100 fuel-efficient A320neos, which have an individual list price of USD 100.2 million, and to purchase 35 standard A320s, each with a price tag of USD 91.5 million in the Airbus catalogue. The contract has been confirmed after initial discussions and a preliminary agreement were reached at the Paris Air Show two last months. \"The agreement was concluded following a thorough technical and economical evaluation and we are delighted that the EasyJet board has now confirmed the order,\" Airbus said in the statement. The A320 family is the world\'s most successful in its category, with over 9, 500 planes ordered and over 5,600 delivered to over 380 customers and operators, worldwide.