(Reuters) -The U.S. Justice Department should take Boeing to trial in a criminal fraud case stemming from two fatal 737 MAX crashes and reject a tentative deal to allow the planemaker to avoid prosecution, a lawyer for some of the victims' families said.

The company was accused of misleading regulators about the jetliner before the two deadly accidents that killed 346 people.

Air Europa has become the first Spanish operator of the Boeing 737 MAX 8 upon welcoming the newest aircraft to its 42-strong fleet.

Boeing expects to stabilize 737 MAX production at 38 airplanes a month over the next couple of months, its Commercial Airplanes Vice President of Quality Doug Ackerman told