Changi is one of only three airports that raked in more than US$1.5 billion (S$2 billion) in spending by travellers last year.
Actual amounts were not stated but Changi was ranked third, behind South Korea's Incheon and Dubai, in a recent study by Swedish duty-free and travel retail consultancy, Generation Research.
Globally, travellers spent a total of US$62 billion at duty-free and airport shops last year, about 3 per cent less than the US$63.8 billion in 2014.
Asia was the only region where spending increased.
Perfumes and cosmetics made up about a third of the total sales, followed by wines and spirits, and fashion and accessories.
With demand for travel in the Asia-Pacific expected to grow in tandem with a burgeoning middle class, airports in the region can expect takings to increase further, said experts.
For Changi, increasing commercial revenue is key to keeping the airport competitive, as part of the takings are used to subsidise aircraft parking and landing, as well as other aeronautical charges.
When Jewel Changi Airport opens in early 2019, travellers will have more reasons to shop at Changi, said lecturer Raine Anastasia Chin from Singapore Polytechnic's business school.
The multi-storey complex being built in front of Terminal 1 will offer mainly retail and dining options.
Ms Chin said: "We expect the retail scene at Changi to pick up significantly when Jewel is done. The idea is to get travellers, especially those in transit, to spend time and, hopefully, money there."
Expanding retail and dining options to boost revenue and earnings is a growing trend among airports worldwide, she said.
"An airport is no longer just a place people go to, to take a flight," Ms Chin added.
To entice even more travellers and visitors to shop, Changi Airport Group reviews and refreshes its offerings regularly, said its executive vice-president (commercial) Lim Peck Hoon.
New brands recently introduced include Spanish clothing and accessories label Zara's first duplex store in an airport, Saint Laurent Paris boutique, Samsung Experience Store, and Garrett Popcorn.
With the demand for chocolates and sweets growing by 20 per cent year on year, in the first five months of the year, Changi is looking to expand product offerings in this range, Ms Lim said.
Another category becoming popular with shoppers is mid-priced fashion, as carried by brands like Charles & Keith, Uniqlo, Giordano and Pandora.
To catch those who may not have much time to shop, the airport's online shopping portal, iShopChangi, which was launched in 2013, now offers more than 6,000 items.
Earlier this month, two new product categories - books and Lego - were introduced.
With the service, travellers can confirm their orders 18 hours to two weeks before their departure flights and pick up the items at any of the designated collection points.
Ms Lim said: "With passengers becoming more well-travelled and retail trends constantly evolving, Changi needs to ensure that our retail strategy and value propositions remain relevant to our shoppers."
Housewife Jane Lim, 36, a Singaporean, said: "It's not just the shopping; there are so many other things to see and do at Changi Airport while waiting for a flight. Some airports are really lame but many of the major hubs do offer a decent range of shopping and dining options."
