"The body was discovered shortly after a maintenance team approached it to carry out routine checks and maintenance," said Khaled Al-Khaibari, spokesman for the General Authority of Civil Aviation (GACA).
"GACA has launched an investigation into the incident and is trying to identity the dead man," he added.
Al-Khaibari said the body has been taken to the airport's hospital for autopsy.
A Nas Air source said there is no evidence to indicate that the plane's pilot or crew knew that a person was approaching the plane at take-off. He, however, could not say what the cause of death was and how the man was able to approach the speeding plane on the runway with a backpack when the flight was about to take off.
Ghazi Aridi, Lebanon's minister of transport, has also ordered an inquiry into the incident.
The plane, an Airbus 320, left Beirut's Rafik Hariri International Airport at 10:50 p.m. Friday and landed at KKIA around 1 a.m. Saturday. The body was found after the plane stopped at the airport's Gate 20.
According to some reports, passengers saw a man with a backpack running toward the plane before it took off from Beirut.
"Any human being can be killed by the speeding tire of a plane or while sheltering inside or along the tires, which are made of rubber, fabric and steel," said aviation expert Nick Kevin.
He added that there is a "possibility that the person would have come in contact with the wheel" and got killed instantly.
Arab News tried to contact Nas Air's official spokesman, Waleed Mohammed Al-Shaikh, director of the airline's marketing and communication. His mobile phone was switched off.
Nas Air operates 14 flights each week from Beirut to Riyadh and Jeddah. The airline began flights to and from Beirut in July 2008.
