The hijacker of an EgyptAir flight, Ibrahim Abdel Tawwab Samaha, is a professor of veterinary medicine at Alexandria University, a staff list on the university website shows.
Samaha is head of the department of food health, the site shows.
The plane was an Airbus 320, Egypt’s aviation ministry said.
Egyptian state media named the hijacker as Ibrahim Samaha, an Egyptian, but gave no other details about him.
Passengers on the plane included eight Britons and 10 Americans, three security sources at Alexandria airport said.
Israel scrambled warplanes in its airspace as a precaution in response to the hijacking, according to an Israeli military source.
Egypt’s vital tourism industry was already reeling from the crash of a Russian passenger plane in the Sinai in late October.
President Abdel Fattah al-Sisi has said it was brought down by a terrorist attack. Islamic State has said it planted a bomb on board, killing all 224 people on board.
Cyprus has seen little militant activity for decades, despite its proximity to the Middle East.
A botched attempt by Egyptian commandos to storm a hijacked airliner at Larnaca airport led to the disruption of diplomatic relations between Cyprus and Egypt in 1978.
In 1988, a Kuwaiti airliner which had been hijacked from Bangkok to Kuwait in a 16-day seige had a stopover in Larnaca, where two hostages were killed.