double-blind study - an experimental procedure in which neither the subjects of the experiment nor the persons administering the experiment know the critical aspects of the experiment; a double-blind procedure is used to guard against both experimenter bias and placebo effects.
No they get more expensive, airlines will always advise you to book in advance to take advantage of their best fares. Sometimes they do a special deal but not within a week of flying. I would try another airline or make different plans.
What's more, researchers found that average ticket prices were fairly flat during the window of time 50 to 100 days before departure. In other words, the best bet is to book 50 to 100 days beforehand: Tickets purchased during that period were $85 cheaper than the overall average for all domestic flight prices ($495.55).