The way the war is developing "does not encourage optimism," Frangialli said and a recovery in the tourism sector "risks being delayed for some time."

He said: "In the short term the main sector concerned is air travel, which is seriously affected and not just in the US," he said.

But in the long term he said he was confident. "The sector has never experienced a long depression. There is always an underlying need to travel," he said.

SPACE.WIRE