Passenger count far below projection figures has prompted a third international airline to pull out of the Calcutta skies in little more than a month. That, however, has not stopped the airlines staying back from planning an increase in flight frequency.

Following the flight path of Royal Jordanian Airlines and Malaysia Airlines, Jetstar Asia, the low-cost carrier to southeast Asia, has announced withdrawal of Calcutta operations from May 1.

Sources attribute the airline?s decision to poor flight occupancy ? 40 per cent, against the break-even target of 75 per cent. A Jetstar official confirmed that the ?passenger load factor was much below the targeted 75 per cent?.

Chong Phit Lian, CEO of Jetstar Asia and Valuair, said on Monday: ?Affected passengers will be offered a full refund or a change in itinerary to the higher-value Bangalore-Singapore sector.?

Low occupancy had earlier felled Royal Jordanian Airlines, which had been flying out of Calcutta for the past 18 years. From a consistent 65 to 70 per cent, occupancy dropped to 35-40 per cent last year.

The official reason for the pull-out of Malaysia Airlines was a funds crunch. But aviation circles also blame the decision on the airline?s switch from the Airbus 330-200 aircraft to the smaller Boeing 737-800 at a time when passenger traffic to Southeast Asia was picking up.

An Airbus 330-200 aircraft has a passenger capacity of 278, but against a break-even target of 65 per cent, it recorded around 35 per cent. In December, the airline changed to Boeing 737-800, with its viability linked to 100 per cent occupancy.

?Most airlines do not conduct proper surveys before starting operations and realise after a few months that flying here is not viable,? said Anil Punjabi, of Travel Agents Federation of India.

Despite the airlines flying away from the city, British Airways is planning to increase the frequency of Calcutta-London flights from thrice a week to six times. Thai Airways is planning to increase the frequency from five to seven times a week and Singapore Airlines from four to five times a week.