Boeing is set to enter into a non-prosecution agreement in the fatal crashes of two 737 Max aircraft that killed hundreds, the US Department of Justice said.

As part of the deal, Boeing will avoid an upcoming fraud trial that could have resulted in the US aviation giant and defence contractor being labelled a felon. The deal includes the company admitting to obstructing federal aviation officials and paying $1.1 billion in fines.

The two crashes, in 2018 and 2019, left 346 people dead.

The government said it had conferred with families of crash victims, and said many either supported or did not oppose the deal. But family members of some of the victims have strongly criticised the agreement.

Javier de Luis, whose sister was killed in the 2019 crash in Ethiopia, expressed his outrage over the decision in a statement released by the lawyers for plaintiffs suing Boeing.

"The message sent by this action to companies around the country is, don't worry about making your products safe for your customers. Even if you kill them, just pay a small fine and move on," he said.

Paul Cassell, a lawyer representing the relatives of the victims, said the families hope to convince the court to reject the deal.

"This kind of non-prosecution deal is unprecedented and obviously wrong for the deadliest corporate crime in US history," he said.

Boeing told the BBC on Friday evening that it had no comment. The US Department of Justice would not comment.

In a court filing on Friday, the Justice Department said Boeing would admit to "conspiracy to obstruct and impede" an investigation by the US Federal Aviation Administration (FAA) and to pay more than $1.1 billion in fines.

Boeing will also have to continue making improvements to its anti-fraud compliance and ethics program.

Boeing's 737 Max models were grounded globally for almost two years after the 2019 crash of a Ethiopian Airlines flight outside of Addis Ababa. All 157 people on-board were killed.

Five months before that, a 737 Max operated by Lion Air crashed into the Java Sea shortly after take-off from Jakarta, Indonesia. 189 people aboard were killed.

Both crashes were linked to faulty flight control systems.

The crashes led to fraud charges against a former top Boeing pilot who was acquitted in 2022.

In 2021, in the closing days of the first Trump presidency, Boeing reached a settlement with prosecutors that protected it from prosecution for three years.

Federal prosecutors said Boeing violated that deal by failing to create and follow a compliance and ethics program aimed at detecting violations of US laws.

A door panel flew off a 737 Max 9 operated by Alaska Airlines two days before the agreement had been set to expire.

Last year, Boeing agreed to plead guilty to criminal fraud in a settlement to avoid trials, but the agreement was rejected by a federal judge who cited concerns that race-based considerations under Biden -era DEI policies would be used in selecting an independent monitor in charge of overseeing Boeing's compliance.

The Justice Department is expected to file a motion to dismiss the case by late next week once the agreement is finalized.

"The Agreement guarantees further accountability and substantial benefits from Boeing immediately, while avoiding the uncertainty and litigation risk presented by proceeding to trial," the Justice Department stated in court papers.

Many victims' families have long pushed for a public trial and prosecution of former Boeing officials, and they have opposed attempts to drop the criminal case.

"It's a sweetheart deal," says Robert Clifford, a lawyer representing relatives of crash victims.

Catherine Berthet, of France, whose 28-year-old daughter died in the Ethiopian Airlines crash said she was "absolutely stunned" by the DOJ's decision to grant Boeing a non-prosecution agreement.

"[T]he government has blind faith in Boeing, to the point of letting it get away with the murder of 346 people, including my so beloved daughter Camille," said Berthet.