As a frequent flier and devout Muslim, businessman Abdalhamid Evans always comes up against the same challenge in the air: when to say his prayers.

Muslims are required to pray five times a day at certain hours, but this schedule becomes complicated when crossing various time zones at thousands of metres above sea level.

"I usually don't pray when I am in a plane," said Evans, the London-based founder of a website that provides information on the global halal, or Islam-compliant, industry.

"But lately I have been thinking that it is probably better to do them in the air than make them up on arrival," he told AFP.

The problem may be solved for travellers such as Evans thanks to an innovation called the Air Travel Prayer Time Calculator, developed by Singapore-based Crescentrating, a firm that gives halal ratings to hotels and other travel-related establishments.

Launched earlier this month, the online tool takes data such as prayer times in the country of origin, the destination city and in countries on the flight path and uses an algorithm to plot exact prayer hours during a flight.

Current programmes only allow Muslims to find their prayer hours according to their position on land, and the absence of any tools that can be used to calculate during a flight has compromised many travellers .

"I knew there was lot of frustration among the travellers on this issue, but nobody had really attempted to solve it," Crescentrating chief executive Fazal Bahardeen told AFP in an interview.

Before embarking on a trip, a Muslim traveller can now go to the online calculator in the Crescentrating website and input their departure airport, time of flight and destination.

The calculator then comes up with the prayer times set either in the local time of the airport of origin, the destination city or the country that the aircraft is flying over, which the traveller can then email to themselves to access later.

Fazal said his team plans to develop a mobile app that will also point users in the direction of the Islamic holy city of Mecca, to which Muslims must face when they pray, based on the flight path.

Muslim travellers have welcomed the tool. "It's good for long-haul travelling," said Shiraz Sideek, a vice president at the Abu Dhabi Islamic Bank who travels almost a dozen times a year.

"When you cross different times zones in an airplane, you have a problem of timing when to pray," he told AFP from Abu Dhabi. "The application sounds like a very unique thing and very useful."

Indonesian airline industry executive Sabry Salahudeen agrees that there is a potentially big market for the new tool.

"I've been in the airline industry for the past 20 plus years... To my knowledge I don't think anyone has come up with anything like this," said Salahudeen, vice president for airport operations and aircraft procurement at Pacific Royale Airways, a soon-to-be-launched premium airline in Indonesia.

As more Muslims travel around the world, services catering to their needs are expanding, industry players say.

In 2010, Muslim travellers spent $100 billion, or about 10 percent of total global travel expenditures, according to Crescentrating's Fazal. This is projected to increase to 14-15 percent of the global total by 2020.

The World Tourism Organization last year estimated that an additional two million Arabs will travel overseas within the next twenty years, raising their region's total of outbound tourists to 37 million.

While it is still early days for the Air Travel Prayer Time Calculator, potential customers say mobility is important.

"If it becomes a smartphone app .. it could prove to be a popular idea," said Evans.