A flight from Warsaw to the Egyptian resort of Hurghada was diverted on Thursday after a passenger warned of a bomb threat. He later admitted to having consumed alcohol.
The plane, with 161 people on board, made an emergency landing at Bulgaria.
The plane was checked after it landed at an airport in Burgas city, and no explosives were found, according to Reuters.
The passengers were evacuated and a man who reported the threat was questioned.
"A 64-year-old passenger reported the bomb and is already being questioned by law enforcers," a Bulgarian news channel reported, according to Sputnik International.
The man admitted to having consumed alcohol, Reuters said later.
The incident comes two days after two Air France flights heading to Paris from the United States were diverted due to bomb threats on Tuesday.
The planes were searched and were said to be safe after they made emergency landings.
This week, Russia confirmed that its passenger plane flying from Egypt's Sharm El Sheikh resort was destroyed by a bomb placed on board while it was flying over the Sinai Peninsula.