By Abhijith Ganapavaram, Aditya Kalra and Aditi Shah NEW DELHI (Reuters) -Indian airlines Air India and IndiGo are bracing for higher fuel costs and longer journey times as they reroute international flights after Pakistan shut its airspace to them amid tensions over a deadly militant attack in Kashmir.

Pakistan's airspace closure to Indian aircraft following the Pahalgam attack has significantly extended flight times, with Delhi-New York routes facing up to four-hour delays and potential 8-12%

Indian airlines may suspend flights to a few destinations where it may be operationally or financially unviable to operate flights that circumvent the Pakistani airspace, according to industry experts.