As pop star Taylor Swift’s “Eras” tour continues throughout Europe, eager American fans have been snapping up flight tickets to catch the concerts.

Demand for United Airlines flights to Lisbon, Portugal, this weekend is up 25% over last year, the air carrier told CNN. Ms. Swift will be performing at the city’s Estadio da Luz on Saturday.

United flights to Milan, Italy, and Munich, Germany, in July, coinciding with more Swift concerts, have 45% more passenger demand versus the same time last year, the airline added.

Americans have made up a sizable portion of concert audiences during the European leg of the tour. Crowds at four shows for Ms. Swift in Paris were 20% American, according to The Associated Press. An additional 10,000 Yanks flocked to Stockholm for a concert there.

Searches on Airbnb in the U.K. cities of Edinburgh, London, Cardiff and Liverpool, where Ms. Swift is playing in June and August, skyrocketed by 337% when concert tickets for those shows went on sale last summer, according to AP.

Stronger European regulations against extra fees and resale markups helped make European tickets and travel no more costly than trying to see Ms. Swift in America.

“They said, ‘Wait a minute; I can either spend $1,500 to go see my favorite artist in Miami, or I can take that $1,500 and buy a concert ticket, a round-trip plane ticket and three nights in a hotel room,” Expedia spokeswoman Melanie Fish told AP.

Favorable exchange rates also helped. The average price of a ticket to one of Ms. Swift’s Parisian concerts was 150 euros, equivalent to $163.

“In France, that’s a lot of money. In the U.S., it’s a tip. What the Taylor Swift concerts show is our relative impoverishment,” Olivier Babeau, chairman of the French think tank Sapiens Institute, told The Times of London.

• Brad Matthews can be reached at bmatthews@washingtontimes.com.