CLEVELAND, Ohio - Wow Air, one of two Iceland-based airlines that started flying from Cleveland Hopkins International Airport in May, won't return to Cleveland next year.

Cleveland is one of several U.S. routes being cut by the low-cost carrier, which is facing financial challenges, likely from growing too fast, according to industry analysts.

Routes from St. Louis and Cincinnati will also be eliminated. Wow's last flight from Cleveland is scheduled for Friday, Oct. 26.

According to a statement from the airline: "Unfortunately, these routes did not perform as we hoped this summer with load factors not achieving the targets that were set for the route in the beginning, and compared to other markets in our network."

A spokeswoman for Wow declined to say what Cleveland's load factors were (that is, the percentage of seats on a plane that are full).

Just last month, the airline, in a press release about fare sales, committed to returning to Cleveland next spring after a hiatus over the winter.

Officials with Cleveland Hopkins Tuesday said they were told by the airline that the route met its load factor goals, but that the flight's yields - that is, the amount of money made per mile flown - were lower than expected. That usually indicates that fares are too low.

Said airport director Robert Kennedy: "The Cleveland market responded well to the low-cost airfares Wow air provided. While we are disappointed with the discontinuation of their service, the strong demand response to Wow air and Icelandair's launch proves that there is a growing demand for transatlantic service from Cleveland."

Wow announced its plans for Cleveland in August 2017 with much fanfare, returning transatlantic service to Northeast Ohio after nearly a decade with no nonstop flights between Hopkins and Europe. Cleveland was one of four new U.S. cities that Wow launched at about the same time, in spring 2018.

Cleveland was unique among those cities, however, in that Icelandair - Iceland's long-time legacy carrier, and Wow's chief competitor - announced new service from Cleveland at the same time.

It's unclear whether the competition from Icelandair in Cleveland contributed to Wow's decision to leave the market. It did not face similar competition in Cincinnati and St. Louis, and is pulling out of those markets, as well.

More likely, Wow is facing financial pressure from competition industrywide, both in Iceland and from U.S. legacy carriers, which have dropped fares to Europe to compete with Wow and other low-cost airlines.

Wow, founded in 2011, offers super-low fares to multiple destinations in Europe, then tacks on extra fees for baggage, advanced-seat assignments, food and other amenities.

Industry consultant Robert Mann said he's not surprised by Wow's retraction. "If you look around the world, ultra-low-cost long haul has really not proven itself," said Mann, with R.W. Mann & Co., in New York. "It's a very difficult business model to make work," especially as fuel prices increase.

Wow last month issued $70 million in bonds, to help refinance debt and fund future operations, according to reports. And even that may not be enough to keep it afloat, said Mann.

Cleveland offered both Wow and Icelandair $1 million each in marketing and advertising support, to be spread over two years, in exchange for the new service. According to the airport, Wow spent just $55,000 of that money, in support of the 2018 Cleveland Marathon and 2018 North Coast Harbor Ice Fest.

Icelandair, meanwhile, announced last month that it was suspending service from Cleveland over the winter months, but would resume the route in late March.

Related: How Cleveland Hopkins scored two flights to Iceland in one week