Aviation in Indonesia serves as a critical means of connecting the thousands of islands throughout the archipelago. Indonesia is the largest archipelagic country in the world, extending 5,120 kilometres (3,181 mi) from east to west and 1,760 kilometres (1,094 mi) from north to south, comprising 13,466 islands, with 922 of those permanently inhabited. With an estimated population of over 255 million people — making it the world's fourth-most-populous country — and also due to the growth of the middle-class, the boom of low-cost carriers in the recent decade, and overall economic growth, many domestic travellers shifted from land and sea transport to faster and more comfortable air travel. Indonesia is widely regarded as an emerging market for air travel in the region. Between 2009 and 2014,