We try to purchase our airfare as soon as flights are released, or very shortly thereafter. Our overwhelming preference is to fly JetBlue (we love the spacious seating, free checked baggage, free seat selection, and TVs on each seat) and we have always found that prices generally steadily increase after the initial release, getting more expensive as travel dates grow closer. The sooner we book, the better the price philosophy has rung true for many trips so far.
In the event that a flight price DOES decrease after booking, some carriers (thinking specifically of JetBlue and Southwest) will offer you a credit for the difference on a future flight, so its worth checking and monitoring until your travel date arrives.
Our next trip is in August 2014. We will book our airfare as soon as JetBlue releases their schedule....probably mid-December, judging by past flight release history. The latest we have booked airfare for August is mid-January. We booked our December 2012 airfare the first week of July 2012.
