Vietnam Airlines has agreed to buy 19 Boeing Co. 787 Dreamliners valued at more than $4 billion at list prices, according to people familiar with the matter.

The order is in addition to the airline's existing orders for eight Boeing 787 Dreamliners, the sources said. All of the airline's 787s, including the new jets, will be powered by General Electric Co. engines, the sources said. GE already is a significant supplier to the airline.

Boeing declined to comment.