Two packages carried by a Turkish Airlines' passenger jet raised alarm at the Sofia Airport on Sunday.
The parcels were found on board the plane that had to take off for Istanbul at 10:05 EET (08:05 GMT).
At the command of airport officials, the aircraft is currently in a remote corner of the airport and does not constitute a possible threat to other vehicles while the packages are being examined over suspicions they might contain explosive devices.
Passengers were not evacuated prior to the inspection which found out nothing dangerous inside the packages.