A police official said a scuffle broke out between the complainant and the pilot onboard the flight last Friday. The woman then approached the Sahar police station in Mumbai and lodged a case, he added.
An Air India spokesperson was not available for comment.
"Based on her complaint, we have registered a case against the pilot under section 354 (assault or criminal force to woman with intent to outrage her modesty) of the IPC", the official said, adding that further investigation is underway.