The flights were cancelled despite the airways management and its pilots last Thursday night hammering out a broad understanding to break the deadlock over the pilots' stir raising prospects of a quick return to normalcy.

The understanding came after Prime Minister Manmohan Singh inquired about the crisis at the Cabinet meeting which was given an update by Civil Aviation Minister Praful Patel.

"Around 15 flights including four international flying from Delhi till afternoon have been cancelled. In total we have cancelled 173 flights from across the country," a Jet Airways spokesperson said.

The airline said in Mumbai that 495 of its pilots reported sick and did not join duty.

"Passengers flying on routes which we don't operate are being transferred to other air carriers and rest of the passengers are flying on Jet Airways and JetLite flights," the spokesperson said.

Most of the passengers had already booked their tickLDets with other airlines apprehending trouble in view of the stir.

Jet airways ticketing counter as well as check-in counter wore a deserted look.

The pilots are agitating since Tuesday demanding reinstatement of their four sacked colleagues.