Frontier is having a promo code sale for 180 specific routes (counting both directions). Take up to 90% off the base fare for late summer/fall travel. Fares start at just $37 roundtrip.

Use promo code AUTUMN when booking on to take 90% off the base fare for specific nonstop domestic flights on Tuesdays and Wednesdays, from August 14 through October 3. Travel on Mondays, Thursdays, Fridays, and Saturdays will be discounted 50% off the base fare within these dates. Avoid blackout dates between August 30 and September 4.

The discount does not apply to taxes nor Frontier's online booking fee, which is labeled a "Carrier Interface Charge". This means some routes still won't have a very big price drop even with the big sticker shock of 90% off. However, there are plenty of routes where we are seeing deep discounts.

The promo code is valid on specific routes only. You may have to click around to find available dates since Frontier operates about half of the route network just a few days each week. Click on the fare details for more info on exact dates each route is available.

Tickets must be booked by 11:59pm ET, on July 23, 2018.

A sample of nonstop fares include:

Austin to Jacksonville $37 roundtrip

Greeville to Orlando $45 roundtrip

Salt Lake City to Las Vegas $50 roundtrip

Atlanta to Orlando $51 roundtrip

Charlotte to Austin $52 roundtrip

Memphis to San Antonio $53 roundtrip

Des Moines to Orlando $54 roundtrip

Detroit to Austin $55 roundtrip

Minneapolis to Raleigh $55 roundtrip

Greenville to Las Vegas $55 roundtrip

Pittsburgh to Orlando $63 roundtrip

Raleigh to San Diego $64 roundtrip

Denver to Boise $67 roundtrip

Buffalo to Jacksonville $67 roundtrip

Milwaukee to Austin $70 roundtrip

St. Louis to Jacksonville $70 roundtrip

Ontario to Orlando $70 roundtrip

Raleigh to Houston $71 roundtrip

Chicago to Long Island-Islip $72 roundtrip

Austin to Charleston $87 roundtrip

San Jose to San Antonio $93 roundtrip

Pittsburgh to San Diego $123 roundtrip

Indianapolis to San Diego $147 roundtrip

Many more routes are available and these fares all work in reverse as well. Lowest fares may not be available throughout the entire travel period. You'll have to decline all extras to get the lowest price.

Keep in mind that Frontier charges extra for any bags larger than a small personal item (small backpack, large purse, etc.). Pack super light to get the lowest price. Checked bag fees start at $25 each way. Larger carry-on bag fees start at $30 each way.

Above image by Colin A. Pierce via Shutterstock.

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