InterGlobe Aviation, the parent of budget carrier IndiGo, slipped back into the red on higher fuel costs and grounding of planes in a seasonally weak quarter.

IndiGo posted a net loss of ₹986.7 crore on Friday compared with a profit of ₹188.9 crore in the corresponding period of the previous year and ₹2,728.8 crore in the preceding three months.

The net loss, which came after seven profitable quarters, was higher than estimates. Brokerages had forecast a loss of ₹130-240 crore.

During the quarter, IndiGo’s revenue increased 13.55 per cent to ₹16,969.6 crore from ₹14,943.9 crore a year ago.

Total expenses jumped 21.9 per cent to ₹18,666.1 crore from ₹15,313.8 crore.

Fuel expenses rose 12.8 per cent ₹6,605.2 crore from ₹5,856 crore.

Aircraft and engine rentals costs soared 290.5 per cent to ₹763.6 crore from ₹195.6 crore.

“IndiGo’s growth and expansion continued as our topline grew by 14.6 per cent on a year-over-year basis in the second quarter to ₹17,800 crore. Our results were impacted by headwinds in groundings and fuel costs, in a traditionally weak quarter,” CEO Pieter Elbers said.

“We have turned the corner as the number of grounded aircraft and associated costs have started reducing. We continue to capitalise on the growth of the Indian market and at the same time remain a cost leader in this competitive market.’’

During the earnings call, IndiGo chief financial officer Gaurav Negi said the number of grounded aircraft will come down to sub-60 level by year-end and further reduce to 40s by the start of the next financial year.

At the end of September, the carrier had a fleet of 410 planes.

Elbers said IndiGo would launch its business class in the Delhi-Mumbai route in two weeks. It will be offered later in 12 other routes.

The airline has also received a positive response to its loyalty rewards programme — IndiGo BluChip.

During the period, the number of passengers increased 5.8 per cent to ₹2,780 crore and the yield — passenger ticket revenue for every revenue passenger kilometer — increased 2.3 per cent to ₹4.55.

Issues with engines made by Pratt & Whitney had grounded more than 70 aircraft last year, weighing on its bottom line, as the airline extended leases on older jets and hired more new ones.

IndiGo has a nearly 63 per cent market share in India and is also Asia’s biggest carrier by market valuation, according to Reuters.

India, the world’s fastest growing aviation market, aims to become a global aviation hub, with airlines, including IndiGo, placing record jet orders.