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.
In general, airlines offer their cheapest flights during business hours, when value-minded business travelers are booking flights. The best single time and day to book a flight is 3 p.m. Eastern time on Tuesday, according to Rick Seaney, CEO of FareCompare. Early morning or late-night flights are less popular, and therefore cheaper. Purchasing a so-called red-eye flight may also save you money.