Against this backdrop, several international airlines are looking at the possibility of jacking up fares by 5-10 per cent, though none has taken a firm decision on this as yet.

"The demand for seats far outstrips supply during winter. The capacity addition in the last two years has made no difference because the increase in the supply of seats has not been in proportion with demand. It is difficult to get economy class seats on the US and European sectors for November, December and January," says Lalit Seth, chairman of the Mumbai-based Raj Travels.

Adds a senior executive of a leading European airline: "We are largely booked for peak winter. We have, however, not taken a final call on the fare increase."

Carriers like Lufthansa, British Airways, United Airlines and Virgin Atlantic are expected to increase the number of flights to India when the government opens up India's skies during winter.

Air-India too will be deploying leased aircraft during these months. In the last 20 months, AI increased seat capacity to the US by 150 per cent.

Besides launching new flights to Australia, Mauritius and Japan on the India-US sector, it is looking at starting direct services to San Francisco, Washington, Houston and Dallas. It will be increasing frequencies on the existing routes, including Chicago, New Jersey, Los Angeles and New York. The number of flights to Toronto will also be stepped up.

Even so, seats on flights will be scarce because demand will outstrip supply, travel industry sources claim.

Around 35,000 seats a week are available on airlines that fly directly to the US from India (AI accounts for around 30 per cent of the total capacity). This excludes the seats of south east Asian airlines which touch down in India, fly to their respective countries and then on to the US.

The passenger rush into and out of India is explained by several factors. Non-resident Indians travel to India to meet friends and relatives during these months.

Foreigners try to escape the extreme winter climate in the US and Europe. Around 70 per cent of the seats are booked overseas, says an international airline executive.