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.
Mr Schulze said that there was no clear single day to find the cheapest deal for all fights. However, when flying to most areas of the world, the cheapest tickets were sold on a Saturday or Sunday. He added that the reason Fridays are so expensive is because airlines launch price hikes then and have already run out of cheap seats.