"An unaccompanied 11-year-old girl was found in the Pulkovo airport of Saint-Petersburg," the transport police of Russia's second largest city said. "She had arrived from Moscow by herself without identification or ticket."
The schoolgirl managed to take the flight without being noticed at any of the security checks, the metal detector at the entrance, check-in, passport control at customs or baggage claim.
A source at the airport told local media that she had passed security procedures by joining a group of adults with several children. She then took a free seat on the plane and was discovered by a flight attendant after takeoff.
The Rossiya carrier which operated the flight from Moscow to Saint-Petersburg said that security procedures were the responsibility of the airport.
"That doesn't mean that we are not taking any responsibility," a company official told AFP, adding that an internal investigation has been launched.
The press service of Saint-Petersburg's Vnukovo airport was unavailable for comment on Wednesday.
Security measures at Russian airports were boosted after a suicide bombing killed 37 people at Moscow's Domodedovo airport in 2011. Airports now require all people and luggage scanned at the entrance to terminals.
