The numbers are growing, even if the answers may not be.

On Sunday, eight airplanes will fly over the southern Indian Ocean searching for missing Malaysia Airlines Flight 370, said Australian Maritime Safety Authority spokeswoman Andrea Hayward-Maher.

That's two planes more than Saturday and the most aircraft involved in the search lead by Australia so far, she said.

Sunday's search will be a visual search, AMSA rescue spokesman Mike Barton told reporters. Eyes will take precedence over radar.

The planes will base their movements on Chinese satellite images of debris and drift modeling, the AMSA said.

On Saturday, searchers found a wooden pallet as well as strapping belts, AMSA's John Young said. The use of wooden pallets is common in the airline industry.

"It's a possible lead...but pallets are used in the shipping industry as well." he said Sunday. Authorities have said random debris is often found in the ocean.

The Sunday search has been split into two areas that cover 59,000 square kilometers (22,800 square miles) about 2,500 kilometers (1,553 miles) southwest of Perth.

Only one ship, the HMAS Success, an Australian naval vessel, will be involved in the Sunday search, Barton said. A Norwegian merchant ship previously involved was released in anticipation of rough weather.

The flying distance to and from the search area presents a big challenge for search aircraft. "They're operating at the limits of their endurance," Barton said. The distance is forcing searchers spread the search out over several days.

Hope, only hope

One official, Australian Prime Minister Tony Abbott, voiced hope.

"We have now had a number of very credible leads, and there is increasing hope -- no more than hope, no more than hope -- that we might be on the road to discovering what did happen to this ill-fated aircraft," Abbott said at a press conference.

In one of the great aviation mysteries in history, the airliner carrying 239 people disappeared March 8 after it took off from Kuala Lumpur on a flight to Beijing, China. An exhaustive search covering 2.97 million square miles -- nearly the size of the continental United States -- has yielded some clues, but no evidence of where the Boeing 777 is or what happened to it.

The international search for the missing aircraft resumed early Sunday near Perth, with a U.S. Navy P-8 Poseidon rejoining the effort, according to a naval spokesman.

Planes from the United States, New Zealand, Australia and China will be flying. All the planes were airborne by 2:30 a.m. ET, the AMSA reported.

NASA satellites to be employed

The P-8 Posideon, grounded for two days to give its crew rest, will likely refocus on an area highlighted in Chinese satellite images of a large object floating in the area. The object the Chinese satellite photographed is 22.5 meters long and 13 meters wide (74 feet by 43 feet), officials said.

But Australian-led search teams in the southern Indian Ocean found no sign of it Saturday.

As a result of the satellite sighting, plans are underway to acquire more imagery within the next few days, NASA said Saturday.

The space agency said it will check archives of satellite data and use space-based assets such as the Earth-Observing-1 (EO-1) satellite and the ISERV camera on the International Space Station to scour for possible crash sites. The resolution of these images could be used to identify objects of about 98 feet (30 meters) or larger.

The floating object reported in the Chinese satellite images was about 77 miles from where earlier satellite images issued by Australia spotted floating debris.

During Saturday's search, a civil aircraft reported sighting with the naked eye some small objects floating, including the wooden pallet, AMSA said. These objects were within a radius of 5 kilometers (3 miles).

A New Zealand Air Force P-3 Orion reported seeing clumps of seaweed, AMSA said.

Debris is a common sight in that part of the ocean and includes containers that fall off ships.

Countries from central Asia to Australia are also engaged in the search along an arc drawn by authorities based on satellite pings received from the plane hours after it vanished. One arc tracks the southern Indian Ocean zone that's the focus of current attention.

The other arc tracks over parts of Cambodia, Laos, China and into Kazakhstan.