Airlines may be willing to sell their remaining seats for summer at a discount, now that most people who plan to fly to their summer vacation spot have already bought tickets.

July 14, 2011 at 1:50PM

A Delta Airlines plane (Associated Press/The Minnesota Star Tribune)

Now that the July 4th Day holiday is over, it's time to look for deals on airfares.

Summer is a make-or-break time for the airlines, so even though summer flights are looking pretty full, especially for July, we could see some deals on those seats that are left. Airlines know that most people who plan to fly to their summer vacation spot have already bought tickets, so they will be willing to sell the rest at a discount.

Airlines typically launch sales on Tuesdays, so that's the best day to look for deals. Lately we've mostly seen three-day sales, but we should also start seeing some seven-day, 10-day and even two-week-long sales.

Airlines also are discounting more summer dates and additional days of the week for travel. Typically, the cheapest days for sale fares have been Tuesday, Wednesday and Saturday, but Southwest's recent blowout sale only excluded travel on Fridays and Sundays.

Deals for travel on Fridays and Sundays will continue to be tough to find because business travelers want to return home on Fridays, and leisure travelers want to depart on Fridays and return on Sundays. Travelers would really benefit from a change in the way they think about departing and returning. If you leave midweek, you can have two short workweeks and save a bundle on fares.

We have seen Hawaii prices go down and then come back up. A couple of weeks ago, fares dipped to the mid-$400 range for travel from July through April 2012. You'll have to be on the lookout to catch those fares if they dip again and be ready to buy, because that is a great price. Winter in Hawaii can make for a nice break, especially if we have another winter like the last one.

Fares to both Cancun and Puerto Vallarta have room for improvement, and we should begin seeing sales for fall travel to Mexico and the Caribbean. We've seen some good fares to Central America, but you'll have to watch out for the fuel surcharges.

Be sure you look at the total fare price before you book. Fuel surcharges can make some international destinations unaffordable, even if the base fare is a bargain.

I've said it before and I'll say it again: It's more important than ever to stay within fare sales when booking tickets. There are temporary, unadvertised sales, and if you find one, buy your ticket.

Tom Parsons is CEO of Bestfares.com: mediabestfares.com.