A Chicago law firm took the first step in filing litigation on behalf of the father of a man who was on the missing plane. The request for documents cites Malaysia Airlines and Boeing, which the made the 777 jetliner.
239 people were on board the flight, including 227 passengers (including one infant and one toddler) and 12 crew members.
Three Americans, including two children, are among the missing. Philip Wood, 50, an IBM executive, had just come from Texas where he was visiting family on his way to Beijing.
There were citizens of 14 different countries on board.
Twenty passengers on the plane worked for the Austin, Texas, company Freescale Semiconductor. Another passenger, Chng Mei Ling, worked as an engineer for the Pennsylvania company Flexsys America LP.
Pilot Zaharie Ahmad Shah, 53, was a veteran pilot who joined Malaysia Airlines in 1981 and had over 18,000 flying hours.