Having completed three years of domestic operations, Vistara, the full-service carrier jointly promoted by Tata Sons and Singapore Airlines, is mulling foray into international skies by the second half of calender year 2018. The airline, which has expanded its network to 22 destinations with over 700 flights a week, will be applying for licence for international service once it inducts the 20th aircraft to its fleet in May. Sanjiv Kapoor, chief strategy & commercial officer, told reporters on Thursday that as per the norms, the airline needs to have 20 aircraft in order to apply for international licence. \u201cAt present, Vistara has 17 aircraft. With the ongoing deliveries, it expects its 20th aircraft in May and by June it plans to add two more, taking the total number of aircraft to 22 by June 2018,\u201d he said. According to Kapoor, the airline would start paper works for obtaining approval to fly overseas by June or July. Kapoor was here to inaugurate the airline's daily direct flights from Chennai to Delhi. Vistara has Airbus A320 aircraft in its fleet and with the type of aircraft, it can fly to destinations which are up to 3.5-4 hours of flying time from Indian airports. Hence, the focus initially would be on countries of south-east Asia and the West Asia, he said. The company is reviewing the type of aircraft it would need to support plans of international expansion. The airline is also planning to induct 2-3 wide body aircraft for long-haul, which will fly for 8-9 hours, by the next year, said Kapoor. On the domestic front, Vistara is looking to add more destinations. \u201cSince we are a full-service carrier, we need to have good corporate travellers and our main focus will be metros,\u201d said Kapoor. On the UDAN scheme, he said though the project was good, it does not fit into its scheme of things as it has bigger aircraft that are not suitable for smaller towns. However, he didn't rule out the possibility of adding smaller aircraft to take on low-cost carriers at least for the leisure destinations. \u201cSuch routes are not only becoming popular, but also becoming profitable, so we may consider in the future,\u201d Kapoor said. According to him, there are two major constraints for Vistara to expand. One is availability of aircraft, and the other is the issues related to infrastructure including availability of parking, among others.