The Coast Guard will end its search for a missing Big Island airplane at nightfall tonight, though the Hawaii County Fire Department will resume its search at dawn Friday.

Deputy Fire Chief Glen Honda said the Coast Guard will suspend its participation in the search, but will rejoin if new evidence or information about the plane is found.

Honda said the fire department will continue searching. Earlier, the fire department said it was prepared to keep searching until Sunday.

The Associated Press reported the names of the two passengers on the plane as Nobuhiro and Masako Suzuki, of Chiba prefecture in Japan. The couple's son has arrived on the Big Island has met with local officials.

Island Hoppers, operators of the tour plane, said today that company staff "continue to be optimistic about a positive outcome" in the search for a missing tour plane.

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

"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 company statement said.

U.S. Coast Guard and Big Island Fire Department crews resumed the search this morning for the Cessna 172 with three people on board that has been missing since Tuesday afternoon.

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

Oliveira said private tour companies may also be searching independently, but said they had not yet notified the county of their efforts.

The air search today 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 finder instruments to drive along the highways along the route Cessna pilot Takahashi, 40, filed before he departed from the Kona airport Tuesday morning.

Takahashi, an experienced tour pilot who had two Japanese nationals as passengers, had planned to travel clockwise around the Big Island from the Kona airport.

The Island Hoppers plane he was piloting was last seen near Kilauea volcano by another Island Hoppers pilot flying in the area.

When Takahashi's Cessna failed to arrive in Kona at about 1:30 p.m. as scheduled, the search began.

Oliveira said the Civil Air Patrol ground crews will travel off the coastal highway to higher elevations to see if they can locate a signal from the plane's emergency broadcasting equipment.

One ground crew will travel south along Highway 11 from Kona, and another is traveling from Hilo through the Volcano area and into Ka'u.

"The reason for that is that area of the island, depending in the weather, cloud cover can come in and we can't get up to the higher elevations,"

Oliveira said. "It will just be another way of seeing if we can pick up something under the bad weather from the ground."

Oliveira said the clearer coastal areas have already been carefully searched from the air, and the Coast Guard will consider how to proceed or whether to suspend the search if nothing is found today. The Coast Guard has said its crews had covered more than 3,000 square miles by dusk yesterday.

If the Coast Guard does suspend its search tonight, the county plans to take over and continue the effort with its helicopters, Oliveira said.

"That's going to be their call, but we're preparing for that," Oliveira said. If that happens "we would be prepared to continue the mission through Sunday," he said.

Island Hoppers plans on "continuing our search for the foreseeable future, utilizing every resource available to us," according to the company statement released today.

An investigator with the National Transportation Safety Board is on the Big Island, and is following up on a report from someone who heard a plane in an area where the Cessna could have been, Oliveira said.

The Coast Guard has also dropped buoys to test the current in the ocean in the general area of South Point where a fisherman reported seeing debris yesterday that looked as if it could have come from an airplane.

A check of that ocean area one to two miles offshore yesterday by the Coast Guard failed to locate the debris, but it may be possible to find it by tracing the current, Oliveira said. Crews will also check the shoreline for debris if it appears the current is headed that way, he said.