One year ago today, Malaysia Airlines Flight 370 disappeared as it made its way from Kuala Lumpur to Beijing.

The search for the Boeing 777, with 239 passengers and crew on board, has covered almost 1.8 million square miles of the southern Indian Ocean, and has involved 82 aircraft and 84 ships from 26 countries, CBS News reported Saturday.

The search has yielded no signs of the plane -- no wreckage, no life jackets, no flotation devices, no luggage, no human remains.

In January, Malaysia's civil aviation authority reportedly declared passengers and crew on board deceased and officially classified Flight 370's disappearance as "an accident." The families were offered $50,000 per victim.

While the announcement allowed the airline to settle any legal obligations and speed up payments to the families of the victims, many of the families who lost loved ones are angry.

"Despite this complete lack of wreckage found or physical evidence of a catastrophic event, the Malaysian government has officially declared that the airplane crashed, leaving no survivors, and it has ended the rescue phase of the search effort," a group called Voice370, which speaks on behalf of the victims' families, said in a statement issued to the press on Friday, CBS reported. "We do not accept this finding and we will not give up hope until we have definitive proof of what happened to MH370."

"I still call the phone."

- Jacqui Gonzales

According to CBS, four ships continue to search the South Indian Ocean and have covered nearly 45 percent of the target area to date.

The one-year anniversary is a difficult time for many victims' families, including Jacqui Gonzales, whose husband of nearly 30 years, Patrick, worked on Flight 370 as an in-flight supervisor. 

"A year of no news, no answers and no Patrick," she told CBS. One year later, Gonzales says she still calls Patrick's cellphone.

"I still call the phone," she said. She doesn't hear his voice, "but the recording of his voice mail. His number is still there."

On Saturday, Malaysia's transport minister, Liow Tiong Lai, told the BBC that search teams would continue to look for Flight 370. Liow said he is confident the plane will be found in the southern Indian Ocean.

Still, according to Liow, if the massive undersea search for Malaysia Airlines Flight 370 turns up nothing by the end of May, the three countries leading the effort will go "back to the drawing board," Malaysia's transport minister said Saturday.

Liow told a small group of foreign reporters on the eve of the anniversary of the plane's disappearance that he remains cautiously optimistic the Boeing 777 is in the area of the southern Indian Ocean where the search is ongoing.

Australian Transport Minister Warren Truss said last week that if the plane isn't found by May, one option is to expand the hunt beyond the current search zone to a wider surrounding area.

Despite the exhaustive search for the plane, which disappeared last March 8, no trace of the jet has been found. Malaysia's government on Jan. 29 formally declared the incident an accident and said all 239 people on board were presumed dead.

"By the end of May, if we still can't find the plane, then we will have to go back to the drawing board," Liow said.

Ships looking for debris from the plane on the ocean floor off the coast of western Australia have so far scoured 44 percent of the 60,000-square-kilometer (23,166-square-mile) area the search has been focused on, Liow said.

In the latest report he received Friday, he said the search team had identified 10 hard objects that still need to be analyzed.

Such findings, which often include trash and cargo containers from passing ships, have been common during the search, and so far no trace of wreckage has been located.

Liow said that Australia, Malaysia and China would meet next month to discuss the next steps in the search. Most of the plane's passengers were Chinese.

The Associated Press contributed to this report.