National Express said: "An empty National Express vehicle caught fire at Gatwick Airport earlier this afternoon. We are working closely with the emergency services and will continue to assist them.
"We will also carry out our own thorough investigation to establish the cause of this highly unusual incident."
More top news
Philippa has Sunday's weather for the east
Philippa has Sunday's weather for the west
Police are hunting a driver who knocked down and killed a woman outside a hospital before driving off.