The airlines domestic operations, however, were unaffected.
"Four flights - Delhi-Toronto, Delhi-Chicago, Mumbai-Newark and Mumbai-Hongkong via Delhi have been cancelled due to unavailability of pilots," an Air India spokesperson said here.
About 100 pilots have so far not reported for duty, the spokesperson said.
A section of Air India pilots owing allegiance to Indian Pilots Guild are agitating over the rescheduling of Boeing 787 Dreamliner training.
A section of Air India pilots had yesterday threatened to strike work following the failure of talks with the Air India management.
"The management (Air India) has completely backtracked from what had been agreed upon in the last 2-3 days. Therefore, we are left with no option but to intensify our agitation," Guild sources had told PTI here.
Disappointed over the management's attitude, some 100 odd pilots have already join the agitation and the Guild expects the number to swell to 250-300 by tomorrow, they had said, indicating the flights operations could be hit severely in the coming days.
Earlier, the management held meeting with the pilots in New Delhi in its bid to defuse the crisis, arising out of the rescheduling of the Dreamliners training programme.
On Saturday, a section of pilots reported sick, apparently to protest the move, resulting in cancellation of one international flight and delaying another two.
It is understood that during their meeting yesterday, the airline management told the pilots that they had no reasons to strike work at a time when the government had announced a bailout package for the national carriers.
The management is also said to have told the pilots to wait for a solution till the Justice D M Dharamadhikari Committee report is implemented by the government.