More: Michelle Cowley, a London-based communications specialist, and her husband spent nearly two years planning a $16,000 vacation to Walt Disney World in Florida. Then their children, ages 7 and 11, heard about Renee Good and Alex Pretti being killed by ICE agents and didn't want to go.

Comments by President Trump in January, including threats to annex Greenland and criticisms of British military contributions in Afghanistan, sealed the family's decision.

"We have decided that it really is not the place we want to be at the moment," Ms. Cowley said.

Even more: "When 11 million international visitors aren't showing up, the result is billions of dollars in economic losses to the travel industry," said Erik Hansen, a senior vice-president at the U.S. Travel Association, a trade group that promotes travel to and within the country.