Following the terrorist attack on the World Trade Center, airports were shut down for two days. There were knock-on effects for cruise lines, hotels, car rental companies, and other travel-related businesses.

One estimate of the cost to U.S. airlines is $2.1 billion this year and next. Trade shows and conventions were canceled or postponed in New York City and elsewhere. Cities lose roughly $1,200 for every person who does not attend a conference. Although they benefited from stranded passengers, hotels are expecting their worst losses in 33 years.

Similarly, car rental companies found their business increasing as people drove themselves home after the attacks, but then suffered from cancellations and cars in the wrong locations. Cruise lines also saw cancellations because passengers could not fly to the port of departure or because they did not want to fly. Theme parks closed for a day and then saw their attendance levels soften, but the effect was small as the peak season is over.

(Updated October 1, 2001)