The message, allegedly written on a lavatory mirror, was discovered shortly before the aircraft was scheduled to take off, according to reports.
After being alerted to the message, the pilot immediately informed Air Traffic Control (ATC), prompting airport authorities to initiate security procedures.
Aircraft moved to isolation bay
Following the alert, officials moved the aircraft to an isolation bay for a detailed security inspection.
Personnel from the Central Industrial Security Force (CISF), along with specialised airport security teams, began searching the aircraft for suspicious objects or materials.
Security personnel were examining different sections of the aircraft as part of the precautionary operation.
The inspection was intended to establish whether the threatening message was linked to any actual security risk.
Police examine CCTV footage
Police and other security agencies have launched an investigation to identify the person who allegedly wrote the message and establish the circumstances surrounding the incident.
Investigators are reviewing CCTV footage from the airport premises and cameras inside the aircraft, according to reports.
The authorities are also examining how the message was written and discovered before the flight's departure.
Further details about the investigation and the outcome of the aircraft search were not immediately available.