Looking for a hot travel deal? Frontier Air is offering fares of $25 one-way to a number of cities.

This deal is valid for travel from September 16 through December 16, 2015, with select blackout dates around the holidays. But you must buy by today Sept. 3, 2015.

I've been checking availability and it is *not* easy to find these seats. They are there, but you may have to fly on an inconvenient day to get the $25 fare.

Frontier, Allegiant, and Spirit all have their own business model that is very different than the full fare airlines. As deep discounters, they'll sell you a ticket and everything else is extra. So know what you're getting before you buy; my briefing about Spirit will give you an idea about the deep discount business model.

Read more: Safety tips for traveling with your pets over Labor Day weekend

When is the best time to buy holiday airfare?

I've been getting a lot of questions about the best time to buy Thanksgiving travel. People are seeing high fares right now and they're starting to get worried.

Well, the truth is a new analysis from Hipmunk predicts that fares are cheaper now than they will be in the coming weeks. So buying now is the right move rather than waiting.

The reality is that the airlines have parked so many planes and reduced the supply of seats that they're in a position to charge very high fares on extreme peak days.

Seasoned travelers know that you'll pay top dollar to fly on the Tuesday and Wednesday before Thanksgiving. The same goes for the Sunday and Monday after Thanksgiving.  So why not consider flying on Thanksgiving day? You can still be there by dinnertime, and fares will be significantly lower that day, as well as the Saturday just after the holiday.

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