1915 The RFC sets up an Accidents Investigation Branch (AIB). After World War I it is also given responsibility for investigating civil air accidents.
1919 The world's first sustained international scheduled service starts flying from Hounslow Heath. The pilots follow landmarks, particularly railway stations that often had their names painted on the roof.
But Hounslow Heath loses its status as London's first airport seven months later as Croydon, which is better placed for continental flights, becomes London's official airport.