Flights across Europe have been disrupted again. It's the third day this week that security threats have targeted passenger planes. Some planes were diverted, while others have undergone security checks. No explosives have been found. Al Jazeera’s Frances Read reports from London's Heathrow Airport. #BombThreats #EuropeFlights #FlightDiversions #AviationNews #AirTravel #EuropeNews #HoaxThreats #AirportSecurity #FlightDisruptions #Heathrow #TravelNews #AlJazeeraEnglish.