But the further grounding of planes came amid hopes of an end to the dispute, as pilots prepared to meet bosses and India's chief labour commissioner in New Delhi to broker a deal.
More than 430 pilots have reported sick since Tuesday in what the company said was a "simulated strike" prompted by the sacking of two senior pilots for setting up an unrecognised trade union.
The action, which the airline calls illegal as conciliation talks had already begun, has led to the cancellation of some 600 flights and the further sacking of two pilots for breach of disciplinary procedures.
Indian media reports on Friday suggested that the situation could be resolved following mediation by a ruling Congress party lawmaker.
"Jet management has agreed to take back all the four pilots," member of parliament Sanjay Nirupam was quoted as saying by the Business Standard newspaper.
A draft agreement thrashed out in late-night talks was due to be discussed at Friday's meeting with the chief la