"Several hours after The Wall Street Journal reported on the talks, Woodward issued a news release saying that it “is not in discussions with Boeing over a possible acquisition of Woodward... After the statement, the people familiar with the matter said the companies remained in talks."
The Wall Street Journal has a long history of thorough research and well-respected publications. There's no doubt that the vetting process for industry sources is extensive. Remember when a right wing group tried to approach the Washington Post with a fake story and how quickly they were able to expose it? It's entirely possible for sources to give occasionally incorrect or unreliable information based on changing events, but the notion that the WSJ consistently relies on "questionable sources" is ignorant of how extensive the process is.
Just because it isn't transparent (which is precisely to protect the quality of their sources) it doesn't mean it isn't reliable.