How much do plane tickets go up if you don't buy them ahead of time?

If you buy a certain kind of ticket (that is more expensive) it is refundable. But that might not really help you.

If you have any mileage on an airline, this would be the time to use it. Make a reservation for what you think the trip dates are, and if you have to change it, no charge.

keep in mind the airline regulations on extra baggage as well. You could be spending at least $80 more for your bags.

It depends on a number of factors. One of them is the airline. Airlines use different methods to sell their tickets. Some have more last minute sales than others. It also depends on the route, the time of year, and like stated above, whether it is refundable or not.

It also can vary if that particular flight has open seats and they are trying to fill them or not.

It is a time of great flux in the airlines. Fuel costs are rising, airlines like United are grounding flights and others by the end of the summer. The grounding for mechanical inspections also threw another factor in, so this summer is not like any other. A few of the airlines, like Southwest, do offer credit on even their non-refundable tickets, should you cancel them or find a cheaper fare. You have to use that credit within a year of the original booking.

In general it is cheaper this summer to buy in advance, but the airlines goal is to fill their planes, so you can find last minute fares that way, sometimes.

for a round trip flight next November:

2 weeks ago $240.
1 week ago $365.
Booked it this week at $423.

Due to rising gas prices.

olddog. Better than one I was looking at YESTERDAY. Yesterday, it was a non-stop that took 2 hours. Today it was cancelled (United) and you have to make a stop and change planes. It is now 3 hours and 25 min and the price was double.