The airline announced on Monday that Walsh has assumed the role after his appointment was first announced in March.Walsh brings more than four decades of experience in global aviation and will work closely with IndiGo's board and management team to build on the airline's operational foundations. Welcoming Walsh, Rahul Bhatia, Managing Director of IndiGo, said: "As IndiGo enters its third decade and stands poised for the next phase of its growth, I am delighted to officially welcome Willie as the airline's Chief Executive Officer."Walsh said he was joining the airline at a pivotal moment. "IndiGo has built a remarkable legacy over the last two decades, establishing itself amongst the largest airlines in the world in a short span of time," he said."With India becoming one of the world's fastest-growing aviation markets, the opportunities ahead for IndiGo are immense. There could not be a more exciting and opportune time for me to join IndiGo than now."He added: "I look forward to working with the entire IndiGo team to build on the airline's success and take it to greater heights globally."Challenges aheadWalsh takes charge at an interesting time for IndiGo. Just days before his appointment took effect, the airline announced it would discontinue its wide-body operations from October 25 and end its damp lease agreement with Norse Atlantic Airways by the end of October.The carrier said the decision was driven by a challenging operating environment caused by ongoing geopolitical tensions, rising costs, airspace constraints, elevated fuel prices and currency pressures.As a result, flights between Mumbai and Amsterdam will be operated using the Airbus A321XLR from 25 October, while services to London Heathrow will be temporarily suspended until IndiGo begins receiving its Airbus A350-900 aircraft.Walsh also inherits an airline that has faced significant operational challenges in recent months.During December 2025 and shortly after, IndiGo cancelled more than 4,500 flights after a severe pilot shortage coincided with the implementation of new Flight Duty Time Limitations (FDTL) rules. The disruption affected hundreds of thousands of passengers across India and resulted in a record fine from the country's aviation regulator, denting the carrier's reputation for reliability.The airline has since also been navigating a challenging operating environment shaped by geopolitical tensions, airspace restrictions and higher operating costs. A veteran aviation leaderThat said, Walsh is regarded as one of the aviation industry's most influential executives, having held senior leadership roles across several of the world's biggest airlines.His career began as a pilot with Aer Lingus before he became the airline's CEO in 2001. He later served as Chief Executive of British Airways from 2005 to 2011, led International Airlines Group (IAG) between 2011 and 2020, and most recently served as Director General of the International Air Transport Association (IATA).At IndiGo, he will oversee the airline's overall management and strategic direction, with a focus on expanding its global network, strengthening commercial strategy, improving operational performance and enhancing the customer experience.Meanwhile, Walsh's move to IndiGo also marks the end of his tenure at the IATA, where he served as Director General before stepping down this year. He has been succeeded by Saadia Zahidi, who became the global airline body's ninth Director General and its first woman to hold the role.