One of the standard practices of public relations is that the best time to release a statement, study, report, press release, etc. that you don't want to get much attention is late on a Friday afternoon or the day before a major holiday, like New Year's. So the fact that NASA decided that December 31 was the right time to release its long-withheld study of commercial airline pilots complaints about the air traffic control system by itself makes you wonder why NASA was trying to bury the information.