Landing on a runway surrounded by fire might not sound like a good idea, but it's better than trying to land without modern instruments in thick fog. This was FIDO: "Fog, Intensive, Dispersal Of" (originally "Fog Investigation and Dispersal Operations"), the Royal Air Force's strange but brilliant scheme that saved thousands of air crew lives. Unlike a lot of World War 2 experiments, this one not only worked, but was deployed around the country. It would have been used in peacetime, too, except for one rather big problem: petrol's really expensive.