I haven't booked yet, but I plan to fly Delta with the pay with miles feature and they went up $100 overnight!!! We are going at the end of October so my question is when is the best time to book?? 3 months out?? Now?? I am kicking myself for not booking last week when they were $100 cheaper
Each flight has numerous categories of fare inventory. Within the economy cabin, the airline uses sophisticated modeling to determine how many seats it can sell at full price and and at various discount levels.
When a flight jumps $100 per ticket, it tends to mean that a cheap category no longer has as much inventory as you need, and you're now seeing the next category up.
It could also mean that an airfare sale has ended or that there has been a major price increase, but such adjustments tend to be less than $100 for domestic flights.
There are two things to try:
Let's suppose you need 4 tickets. Look for 3, 2, or 1 tickets. You may still see the lower cost if there are 3, 2, or 1 tickets left in cheaper fare inventory. Then you only have to buy the remaining tickets at the higher price.
Try looking after midnight (or after 1 a.m.) to see if any cheap inventory has been replenished because tickets were cancelled. Unfortunately for you, this works much better with American than with Delta because American allows customer to put tickets on a free "24-hour hold" (actually until 11:59 p.m.Central); when they're not purchased by the deadline, they go back into their original inventory.
As others have noted, there's no magic answer on when to buy tickets.