On Friday, five planes, including three P-3 Orions, made the trip. While search conditions had improved from Thursday, with much better visibility, the Australian Maritime Safety Authority said there were no sightings of plane debris.
Searchers relied mostly on trained spotters aboard the planes rather than radar because radar found nothing in the first day of the search Thursday, Australian officials said.
The search will focus more on visual sightings because civilian aircraft are being brought in. The military planes will continue to use both radar and spotters.
"Noting that we got no radar detections yesterday, we have replanned the search to be visual. So aircraft flying relatively low, very highly skilled and trained observers looking out of the aircraft windows and looking to see objects," said John Young, manager of the maritime safety authority's emergency response division.