The nation's airlines are sweating over an unexpected drop in business travel in the last few weeks — and that's welcome news if you're a traveler looking to save money.

This month, domestic airfares are down 5% from September 2019 and international fares down about 8%, drops that industry experts attribute partly to the traditional price slump that happens at the end of the peak summer travel season plus the rise in coronavirus cases due to the Delta variant, according to the travel website Hopper.

Prices for flights to Europe are at a five-year low, down more than 30% compared with the same month in 2019, according to the travel website.

But the discounted prices are not expected to last long, with increases likely when travelers start booking holiday trips.

“Everything we are seeing says people are definitely going to be traveling,” said Adit Damodaran, an economist for Hopper.

The airfare roller coaster shows how the pandemic continues to affect the nation's $1.5-trillion travel and hospitality industry. For the first time since COVID-19 took hold in spring 2020, travel demand this summer began to match and briefly surpass pre-pandemic levels, giving airline executives hope that the industry would soon rebound from more than a year of financial losses.

But in the last few weeks, airlines have reported a steep drop in demand and an increase in reservation cancellations. September typically marks the end of the peak summer travel season and the start of business travel for conferences, conventions and meetings. Industry experts say the uptick in business travel never materialized because of the surge in COVID-19 cases.

As a result, airlines are forced to drop prices to fill the seats left empty by business travelers.

“In a normal year, the fares would stay high because people would travel for business, but that is just not happening,” said Madhu Unnikrishnan, editor of the publication Airline Weekly.

The average domestic round-trip flight costs $260, down from $290 at the end of August, according to Hopper. International round-trip fares have dropped to an average of $700, down from $760 at the end of August.

The average round-trip price of a flight to Europe from the U.S. is $565, down from $665 at the end of August and the lowest price in five years, according to the website's data. That price was an average of $940 at this time in 2019.

But flying to Europe could become more difficult soon. The European Union recommended this week that its 27 nations reinstate restrictions on tourists from the U.S. because of rising coronavirus infections. The guidance isn't mandatory, and member countries have the option of allowing fully vaccinated U.S. travelers in.

The slump in business travel and rise in overall cancellations have airlines worried. Southwest, United, Delta and American airlines all revised their earnings outlook for the July-to-September quarter.