As we've said many times, the best airfare deals are only sometimes available on the airlines' own web sites, and many of them come in the form of promo code deals and special offers. You can only get these, in some cases, if you sign up for alerts and emails directly from the airlines. However, we've noticed that many airlines make it a bit challenging to find where to sign up for alerts! So we've gathered links to most US airlines all in one handy dandy place.  So sign up and save! (Enough email already? Airfarewatchdog lists any and all promo code and special fare sales on the AirfarewatchdogBlog).

Click on any airline below to sign up for newsletters and fare alerts Examples of what you will receive
 Alaska Weekly discount promo code offers, usually in the 10% range.
 Allegiant Air  Must register for as an Allegiant Air member. Promo code offers and sale notices.
 American  Must register for the AAdvantage program. You can register separately for their DealFinder program, but we haven't seen too many enticing offers lately.
 Delta  Must register for the SkyMiles program. Sale announcements including weekend fares.
 Frontier  Sale annoucements incuding weekend fares.
 Hawaiian  Register for the "Low Unadvertised Fares Email" located on the airline's website. Special website-only deals and other sale anouncements.
jetBlue  Promo code sale fares, sometimes 20% off or $30 off, sometimes incredible deals that available on site only such as a recent $14 coast to coast sale.
 Southwest  Incredible 50% off promo code deals and other fare sales.
 Spirit Spirit's loyalty program ($9 Fare Club) involves a yearly fee. Promo code offers and wacky sales with fares as low as $2 plus tax.
 Sun Country Recent offer including $39 companion fares and other deals available only on their web site.
 United  Must register for the Mileage Plus program. No longer sends out weekly weekend fare emails but offers other sale announcements, usually no great shakes.
 Virgin America  Must register for the Elevate loyalty program to get alerts. Best deal they've had so far was a 2 for 1 offer, but we've seen 35% promo code deals as well.

Follow Airfarewatchdog @airfarewatchdog on Twitter to get late-breaking airfare sales. It's faster than email alerts!

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