Also on Wednesday, Bjørn Kjos, the chief executive of Norwegian Air Shuttle said in a series of posts on Twitter about the revised software that the new fix appears "foolproof." The software is believed to be a, or the, factor in the crashes of the 737 MAX in Ethiopia and Indonesia.

"I hope the regulators will have safety in focus as always and not be directed by politics. I will gladly take my family on board a Norwegian MAX," said the CEO, who added that he was in a MAX simulator and tried out updated and older version of the software "under a malfunction."