India's air travellers will have the choice of a fourth domestic carrier from May.

The airline known as North Star Aviation was formed by a group of Indian pilots living in the US and will initially serve at least 20 destinations.

"There is enough room for another airline since the country of one billion [people] has just three airlines,'' Captain Rajiv Jha, chairman and managing director of North Star Aviation told the BBC's World Business Report.

India opened its skies to private airlines in 1994 and already has three domestic carriers; Jet Airways which has a 40% market share, Air Sahara with about 8% and state-run Indian Airlines which controls the rest.

CaptainRajiv Jha was a former pilot with Indian Airlines.

Travel downturn

The new airline will launch at a time when there has been an overall decline in air travel in India.

The factors behind the slowdown include the economic slowdown, a decline in overseas visitors, Hindu-Muslim violence, tensions between Indian and Pakistan and the US-led war in Afghanistan.

Both Indian Airlines and Jet Airways have reported passenger load factors - the average percentage of seats filled per flight - below last year's levels.

But Mr Jha is undeterred by the downturn.

"There's been 4% to 6% annual growth," he said adding the industry had shown incredible "resilience" after the US attacks.

A recent cut in travel agent commissions by Indian Airlines is also expected to favour North Star.

"This cutting of commissions to travel agents comes as a fringe benefit for us," he said.

North Star plans to launch with a fleet of five Airbus 320s or Boeing 737s.

The competition

Jet Airways, founded in 1992 and owned by entrepreneur Naresh Goyal, has 38 relatively new planes and operates 245 flights daily to 44 domestic destinations.

It has grown quickly at the expense of Indian Airlines which has a much older fleet of 56 aircraft making 210 flights daily to 85 destinations, 68 of them domestic.

Air Sahara operates nine Boeing 737s and plans to acquire more soon.