New Delhi, May 1 -- Air India expects to face around $600 million in additional costs if a ban from Pakistan's airspace lasts for a year, and has asked the federal government to compensate it for the hit.

According to news agency Reuters, Air India on April 27 asked the Indian government for a "subsidy model" proportionate to the economic hit, estimating a loss of more than 50 billion Indian rupees ($591 million) for each year the ban lasts, according to a letter sent by the airline to the Civil Aviation Ministry seen by Reuters.

Indian airlines are bracing for higher fuel costs and longer journey times after Pakistan shut its airspace to the country's carriers in a tit-for-tat retaliation following an attack on tourists in Kashmir last...