HILO, Hawai'i — The Coast Guard ended its search for a missing tour plane last night, but county officials said they plan to use Big Island Fire Department helicopters to continue at least through Sunday to try to find the aircraft.

Deputy Fire Chief Glen Honda said the Coast Guard would rejoin the search if new evidence was found.

Big Island Mayor Harry Kim yesterday briefed the adult son of the Japanese couple who were on the missing flight with Island Hoppers pilot Katsuhiro Takahashi, 40.

Kim said the son arrived from Japan yesterday with two uncles to monitor the search, and the relatives made arrangements "so we can maintain close contact with them."

A Japanese official identified his parents as Nobuhiro and Masako Suzuki, 53, and 56, from Chiba prefecture.

Island Hoppers released a statement yesterday saying the company staff "continue to be optimistic about a positive outcome."

Wendy Hart, general manager for Island Hoppers, said Takahashi was a senior pilot and chief flight instructor for the company, a person "in whose skills and abilities we have the greatest confidence."

Island Hoppers plans on "continuing our search for the foreseeable future, utilizing every resource available to us," according to the company statement. "We are extremely appreciative of the tremendous support that has been shown by many other commercial aviation operators as well as private pilots on the island."

The Coast Guard said it will continue to monitor the area for a signal from the missing plane's emergency locating transmitter, using a search-and-rescue satellite system.

"It's always a difficult decision when we suspend a search," said Lt. Cmdr. Kevin Floyd, supervisor of the 14th Coast Guard District's command center in Honolulu.

Coast Guard and fire department crews searched for a third day yesterday for the Cessna 172 Skyhawk that disappeared Tuesday afternoon.

The Coast Guard fielded a C-130 and a UH-65 helicopter to lead the search yesterday, with the county fire department contributing two search-and-rescue helicopters, said Fire Chief Darryl Oliveira.

The air search yesterday focused on the southern half of the Big Island, the area the pilot of the tour plane was expected to pass over after leaving Hawai'i Volcanoes National Park.

The Civil Air Patrol also dispatched ground teams with radio direction finders to drive on the highways along the route the pilot filed before he departed from the Kona airport.

Takahashi, an experienced tour pilot, had planned to travel clockwise around the Big Island from the Kona airport. The plane he was piloting was last seen near Kilauea volcano by another Island Hoppers pilot flying in the same area.

The Civil Air Patrol ground crews traveled off the coastal highway to higher elevations to try to detect a signal from the plane's emergency broadcasting equipment in areas where cloud cover hampered the search from the air. The crews found nothing, fire officials said.

The Coast Guard also dropped buoys to test the ocean current near South Point, where a fisherman reported seeing debris Tuesday that looked as if it could have come from an airplane. A check of that area one to two miles offshore yesterday by the Coast Guard failed to turn up the debris.

Honda said the buoys demonstrated that wreckage northeast of South Point would have washed ashore, and debris northwest of South Point would have drifted into an area about 35 miles offshore.

Checks of both areas turned up nothing, he said.