Hellfire missile
A Hellfire missileEthan Miller / Getty Images

Passengers may not be allowed to carry water bottles through airport security but somehow two Hellfire missiles ended up on a commercial passenger flight destined for Maine.

The missiles turned out to be dummy rounds used for army training in Lebanon, where the flight originated. They posed no danger and were being shipped back to a US company called Orbital ATK, according to a report in the Oregonian.

But airline and airport officials apparently were not aware there were missiles on board, and the FBI initially stepped in to investigate when alerted by rattled authorities in Serbia, where the plane touched down before continuing on for the second leg of its journey to the US.

The American-made dummies had been packed in wooden coffins on the unidentified airliner and were unloaded at Belgrade's Nikola Tesla Airport for inspection, according to the Serbian state news agency Tanjug. That's when a bomb-sniffing dog detected the missiles. Documents identified them as AGM-114 Hellfire missiles destined for Portland, Maine.

The State Department eventually confirmed that "inert training rounds were shipped by a private US company Orbital ATK under the Foreign Military Sales program to integrate the Hellfire Missile System into aircraft operated by the Lebanese Armed Forces."

Hellfire training missiles going astray is not unheard of. In mid-February, Cuba finally returned a dummy missile that was used in a NATO training exercise then apparently vanished in 2014.

After the war games it was taken to Germany and sent to Charles de Gaulle Airport in Paris to be delivered to Florida – its final destination. Instead, it was loaded onto an Air France flight bound for Havana.