A rebound in Hawai'i's visitor arrivals and spending gathered momentum in March, boosting sales at many businesses.

Industry leaders say they expect the gains to continue in the months ahead given the number of flights to Hawai'i being added by airlines this spring and summer.

Visitors arriving in the Islands rose for the fourth straight month to 607,709 in March, a 9.3 percent increase over the same month a year earlier, the Hawaii Tourism Authority reported yesterday. Those arriving by air spent $874 million, nearly $100 million more than the previous March. The jump in spending was the largest in four years.

The added spending should translate into more jobs and lower the state's unemployment rate, which has been stuck at around 6.9 percent for the past year. That's the highest level since 1978.

Harley-Davidson rentals at EagleRider in Lahaina, Maui, have nearly doubled from a year ago, said Colin Bellows, one of the business's three employees.

"We were doing about two or three last year, and now its up to five or six. We've had as many as 10 out at one time," Bellows said.

If the volume continues to grow, the company plans to add more motorcycles and hire another employee, he said.

Maui was the state's hot spot in March, welcoming 14.2 percent more visitors who spent 25.2 percent more than Maui visitors did a year earlier. Arrivals on Oahu and Kauai were fewer but still solid — up 9.5 percent and 8.2 percent respectively. Arrivals were up 2.5 percent on Lanai and 0.2 percent on the Big Island, while Molokai experienced a 3.4 percent decline.

"It's encouraging to see tourism in our state stabilizing," said Marsha Wienert, state tourism liaison.

"Year-to-date we continue to be optimistic about growth from beyond the U.S. and Japan," Wienert said, pointing to the small but growing Korea and China markets.

Of the major markets, Canada led the way with the number of visitors rising by 17.3 percent in March to 50,745. Canada has been the top performing market every month so far this year, thanks to the addition of flights from Edmonton, Calgary, Vancouver and Victoria beginning in December.

For March, the number of airseats from Canada rose 46 percent from a year earlier, according to data from the Hawaii Tourism Authority. Airseats from all points of origin were up 6.6 percent in March. For the April-to-June period the number of airseats is forecast to rise by 5.1 percent from a year earlier.

HTA, which is responsible for marketing Hawai'i as a destination, is working to build on the momentum, said Mike McCartney, the organization's president and chief executive officer .

"We cannot let up and must continue to work even harder to drive demand to fill the additional seats we have attracted into the market, and we need to pay attention to factors such as currency exchange rates and oil prices, which directly affect people's ability and decision to travel to Hawai'i," he said.

"Business has been tremendous — very, very good," said John Chism, a manager at Skyline Eco Adventures, which runs two zipline locations on Maui. "We were just talking about the comparison with last year and how much things have improved."

A year ago a zipline tour could be booked with little advanced notice, Chism said. Now the booking lead time is three days. However, it still doesn't compare to the "heyday" during the last boom when zipline tours needed to be booked a month or more in advance, he said.

Skyline Eco Adventures, which bills itself as the first zipline tour operator in the country, charges $150 for a four-hour tour at its location on the slopes of the West Maui mountains, and $100 for a 1 1/4-hour session at its operation near the base of Haleakalā.

Rich Goodenough, owner of Maui Downhill Bicycle Safaris, said his business is up about 10 percent from a year ago. He said demand was particularly strong during the recent spring break. He was forced to turn away customers because the National Park Service limits the number of people he can take into Haleakalā National Park, the starting point for a downhill tour popular with visitors.