NEW YORK (NYTIMES) - Singapore Airlines added nine weekly flights to India last year, bringing its total to 104. Air France-KLM is increasing its seat capacity on Indian flights by 25 per cent this winter. United Airlines has just begun offering nonstop seasonal daily flights from San Francisco to Delhi. And Delta Air Lines began non-stop service between Kennedy International Airport in New York and Mumbai in December.

In the past few years, more than 20 of the 80 international airlines that fly to India have added service, in some cases through arrangements with other airlines, called code sharing. Travel between the United States and India increased 10.3 per cent from the first half of 2018 to the first half of 2019, American Express Global Business Travel reported.

At this pace, India is expected to become the third-largest aviation market by 2024, behind China and the US, according to the Centre for Aviation, a company that provides market intelligence to the aviation and travel industry.

The uptick in flights, experts say, is the result of a variety of economic, social, immigration and travel trends. More international social media and tech companies are setting up shop in India or increasing their staff. A growing number of Indians are living and working in the US, Canada, Britain and elsewhere, and that means more homeland visits for traditionally close-knit Indian families.

Tourism continues to rise. The contribution of travel and tourism to India's gross domestic product - the broadest measure of goods and services produced in India - is expected to increase to US$492.2 billion (S$662.3 billion) in 2028, from US$234 billion in 2017. The World Travel and Tourism Council ranked India third among 185 countries in terms of tourism's total contribution to the national economy in 2018. It was seventh in 2016.

The international airlines have also increased the flights in the wake of the collapse of Jet Airways in April 2019, which in 2018 accounted for nearly 20 per cent of passengers flown by Indian airlines, and the slow decline of the Indian government-owned carrier Air India.

While there are signs of an economic slowdown in India, business travel to India remains strong. And driving that travel is bilateral trade, said Gunjan Bagla, managing director of Amritt Ventures, a company in Malibu, California, that helps Western companies market their products and services to India.

"When I started my company in 2003, bilateral trade between India and the US was US$16 billion," said Bagla, who is also the author of Doing Business in 21st Century India. "Now it's $142 billion. That means more executives are flying back and forth hashing out deals face to face."

In addition, he said, he sees indications that the Indian government "has become more business friendly."

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Raymond Kollau, founder of the aviation research agency Airline Trends, said that while studies showed that well-established aviation regions like Europe and North America would continue to grow, "the global economic centre of gravity is shifting from the West to emerging Asian countries, which means more airlines are looking east before they look west."

He cited an Airbus forecast of a steeper increase in air trips per capita in India and China from 2018 to 2038 than in the US. The forecast attributed the rise to a faster-growing middle class in emerging countries than in mature Western nations.

Stéphane Ormand, vice president and general manager of Air France-KLM USA, said the economic growth in India, despite fluctuations, still exceeded China's. "Basically," he said, "that's triggered our focus on India now." He continued: "It was very different 15 years ago, when China was growing fast. Now, India is growing faster than China. Their improved infrastructure - roads, airports, electricity, better connectivity - all make travelling and working there easier."

Ormand singled out the Texas market, with its oil, technology and medical companies and their ties to India.

Not only are airlines adding flights to and from India, they're also bringing more Indian culture to the in-flight experience. Many are offering more films in regional dialects and menus with dishes that reflect India's diverse culinary tradition.

British Airways, which last summer increased its weekly flights between India and London to 56 from 49, offers films in Hindi, Tamil, Marathi, Punjabi, Telugu and Bengali. Meanwhile, Lufthansa, which already operates daily nonstop flights from Frankfurt and Munich to four Indian cities and will start five-day-a-week flights in April between Munich and Bangalore, shows films in Telugu, Tamil and Hindi, along with five television shows in Hindi.