(CNN) The search for the passenger jet and the 239 people on board is now in its 12th day, covering a total area roughly the size of the continental United States.
Searchers from 26 countries are trying to pinpointing the plane's location somewhere along two vast arcs, one stretching deep into the Asian landmass, the other far out into the Indian Ocean.
Here are other highlights from the news conference:
-- Some data had been deleted from the flight simulator found at the home of the pilot, Hishammuddin said. Forensic work is under way to try to recover it, he said.
-- Malaysian authorities have received background information from all countries with passengers on board the plane except Russia and Ukraine. So far, no information of significance has been found about any passengers, Hishammuddin said.
-- Malaysia has received some radar data from other countries, he said, but "we are not at liberty to release information from other countries."
-- Reports that the plane was sighted by people in the Maldives are "not true," Hishammuddin said, citing the Chief of the Malaysian Defense Force who contacted his counterpart in the Maldives.
The Malaysian media is also reporting that a half-dozen landing strips were found on the flight simulator inside the home of the 53-year-old pilot. Those include landing strips in the Indian Ocean, Maldives, and Sri Lanka.
The FBI is reviewing the hard drive on the flight simulator taken from the home.
The latest news conference took place as the clock ticked on search efforts.
The box containing the flight-data and cockpit-voice recorders of the missing plane has batteries designed to keep it sending out pings for 30 days. That leaves 18 days until the batteries are expected to run out.
Investigators hope the recorders may reveal vital information about why the passenger jet carrying 239 people veered dramatically off course and disappeared from radar screens. But they have to find them first.
"The odds of finding the pinger are very slim," said Rob McCallum, an ocean search specialist. "Even when you know roughly where the target is, it can be very tricky to find the pinger. They have a very limited range."
Technology put to use
Some of the nations involved in the hunt are deploying an impressive array of technology, including satellites and high-tech submarine-hunting planes, as they try to narrow the search area.
They're also trawling through existing radar and satellite data for clues.
Australia said Wednesday that the area of the southern Indian Ocean where it is searching for the plane has been "significantly refined."
The new area is based on work done by the U.S. National Transportation Safety Board on "the fuel reserves of the aircraft and how far it could have flown," said John Young of the Australian Maritime Safety Authority.
But Australian ships and aircraft have so far seen nothing connected to the missing plane, Australian authorities said.
Small details emerge
Much of what has emerged in recent days has filled in a few more details about the early part of the missing Boeing 777-200's flight.
But clear information on what went on in the cockpit and where exactly the errant jet went after it vanished from Malaysian military radar remains frustratingly elusive.
On Tuesday, for example, a law enforcement official told CNN that the aircraft's first major change of course was almost certainly programmed by somebody in the cockpit. The change was entered into the plane's system at least 12 minutes before a person in the cockpit, believed to be the co-pilot, signed off to air traffic controllers.
But that disclosure only left more questions about the reason behind the reprogrammed flight path.
Some experts said the change in direction could have been part of an alternate flight plan programmed in advance in case of emergency; others suggested it could show something more nefarious was afoot.
And Hishammuddin said Wednesday that "there is no additional waypoint on MH370's documented flight plan, which depicts normal routing all the way to Beijing."
The Thai military, meanwhile, said it had spotted the plane turning west toward the Strait of Malacca early on March 8. That supports the analysis of Malaysian military radar that has the plane flying out over the Strait of Malacca and into the Indian Ocean.
But it didn't make it any clearer where the plane went next. Authorities say information from satellites suggests the plane kept flying for about six hours after it was last detected by Malaysian military radar.
Who was at the controls?
Figuring out who that might be has so far left investigators stumped.
Particular attention has focused on the pilot and first officer on Flight 370, but authorities are yet to come up with any evidence explaining why either of them would have taken the jetliner off course.
And some experts have warned against hastily jumping to conclusions about the role of the pilots.
"I've worked on many cases were the pilots were suspect, and it turned out to be a mechanical and horrible problem," said Mary Schiavo, a CNN aviation analyst and former inspector general for the U.S. Department of Transportation. "And I have a saying myself: Sometimes an erratic flight path is heroism, not terrorism
China says it has found nothing suspicious during background checks on its citizens on the flight -- a large majority of the plane's passengers.
Searchers face deep ocean
Hishammuddin, the country's public face of the search efforts, has repeatedly said at news conferences that little is likely to be established about the mysterious flight until the plane is found.
But in the Indian Ocean, where Australia and Indonesia have taken the lead in the hunt, some of the depths searchers are dealing with are significant.
The Bay of Bengal, for example, which lies between Myanmar and India, has depths of between about 4,000 and 7,000 meters (13,000 feet and 23,000 feet), according to McCallum.
Wreckage and bodies of passengers from Air France Flight 447, which crashed into the Atlantic Ocean in 2009, were found at depths of around 12,000 feet by unmanned submarines.
It took four searches over the course of nearly two years to locate the bulk of the wreckage and the majority of the bodies of the 228 people on board Flight 447. It took even longer to establish the cause of the disaster.
Right now, authorities don't even know for sure if the missing Malaysian plane crashed or landed -- or where.
CNN has talked to more than half a dozen U.S. military and intelligence officials who emphasize that while no one knows what happened to the plane, it is more logical to conclude it crashed into the Indian Ocean.
CNN's Brian Todd, David Fitzpatrick, Kyung Lah, Mitra Mobasherat, Atika Shubert, Evan Perez, Mariano Castillo and Catherine E. Shoichet contributed to this report.