(Reuters) - With hundreds of millions of passengers streaming through its more than 5,100 outlets worldwide, Switzerland's Avolta is quietly amassing a vast "data lake" which it is increasingly using to fine-tune and expand its retail business.

One such insight, Avolta Chief Executive Xavier Rossinyol told Reuters on Thursday, is that the number one spirit now being bought by travellers from India is tequila, while traditionally they were expected to favour whisky or cognac.

While the ability to track what passengers at airports from China to Canada and other tourist locations are spending their money on, either on food and drink or shopping, has not yet turned Avolta into a "data company", it is heading in that direction, Rossinyol said in an interview.

"Ask me the question again in two years, and probably the answer will be different if things work like they are in our head," said Rossinyol, after Avolta posted quarterly turnover of 2.83 billion Swiss francs ($3.14 billion).

Avolta, the re-named group which emerged from the combination of Dufry and Italy's Autogrill, feeds the information into a "data lake" using Microsoft software, but without outsourcing any of the proprietary data.

Rossinyol said the Basel-based company is working to combine the data it has with that of its partners, mainly airports as well as with the major brands it deals with on a global level.

"Sometimes they have a vertical understanding because they understand very well what happens at their airport, but not necessarily globally," said Rossinyol, whose company offers brands ranging from Hugo Boss to Coca-Cola.

Rossinyol is also looking to increase Avolta's conversion rate by creating experiences to engage the 70% of airport passengers who do not spend money in its outlets.

"Some people go with children and might be buying something in the shop where you have something entertaining, a clown or a magician because then it entertains the people and they can shop. So this business is absolutely fascinating," he said.

While geopolitical tensions around the world may have local impacts, Rossinyol said that Avolta's business was largely insulated from situations such as the Middle East conflict.

"If there is a crisis in the Eastern Mediterranean, they (holidaymakers) go to the Western Mediterranean," he added.

Meanwhile, events such as the Paris Olympics and the Euro soccer championships were not expected to lead to any significant change in the number of travellers using Avolta's shops, bars and restaurants.

Rossinyol also sees a "positive trend" of recovery in the number of Chinese travellers venturing abroad, although some of their destinations have changed since before the pandemic.

Earlier this week, Frankfurt Airport operator Fraport said it expects Chinese passengers figures to reach pre-pandemic levels by the end of the year.

($1 = 0.9019 Swiss francs)

(Reporting by Paolo Laudani and Ozan Ergenay; Editing by Alexander Smith)

By Paolo Laudani and Ozan Ergenay