NEW DELHI: India remained the world's fastest growing domestic aviation market for the third straight year in 2017 as economic and network expansion bolstered the sector, according to global airlines' body IATA Globally, Revenue Passenger Kilometres (RPKs) -- a measure of passenger volumes -- rose by 7.6 per cent in 2017, registering "above-trend growth" that was ahead of the ten- year average rate of 5.5 per cent."The domestic India market posted the fastest full-year growth rate for the third year in a row (17.5 per cent), followed by China (13.3 per cent)," the International Air Transport Association (IATA) said in a report released last week.The grouping noted that such growth rates were driven mainly by the comparatively strong rates of economic expansion seen in each country, as well as stimulus from additional airport pairs being offered.Such new services translate into time savings for passengers and have a similar stimulatory impact on demand as cuts in airfares, it added."India posted the fastest domestic RPK growth for the third year in a row, driven by economic and network expansion," the report said.In December also, India registered the highest growth rate of 17.4 per cent.Many Indian carriers have embarked on ambitious expansion plans and local airlines have placed orders for over 900 aircraft.Since late 2014, lower airfares have helped in boosting passenger growth -- which in 2017 was also supported by broad-based pick-up in global economic conditions.This year, IATA said that full-year RPK growth is expected to slightly slower than recorded in 2017."This is mainly because increases in airline input costs -- notably fuel prices but also labour costs in certain countries -- mean that we are unlikely to see the same degree of demand stimulation from lower airfares in 2018 than we have in recent years," the grouping said.IATA represents some 280 airlines comprising 83 per cent of global air traffic.