Another day, another fare sale.

Just a day after Southwest rolled out one of its two big annual fare sales, JetBlue has come out with a sale of its own – a flash sale with fares as low as $31 each way.

However, unlike Southwest’s sale, JetBlue’s sale is extraordinarily targeted. Loosely pegged to Halloween, JetBlue's lowest “slasher” sale fares are only available on a few individual dates between Oct. 27 and Nov. 4.

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But for bargain-seekers with flexibility to thread the sale’s narrow needle, flights are available for as little as $31 each way -- or $62 round trip -- on a number of JetBlue’s non-stop routes. They include offerings such as Boston-Atlanta; Washington-Hartford; San Francisco-Long Beach, Calif.; and Chicago O’Hare-New York JFK.

Perhaps the best bargains are the $31 one-way fares on longer routes – pairings like Denver-New York and Fort Lauderdale-Long Beach. Still, deal hunters must remember that the sale offerings are extremely limited, offered on just a few days during that Oct. 27-Nov. 4 window.

One bright side: Since the sale fares are one-way, they can be combined with other one-way fares, either on JetBlue or another airline.

Regardless, JetBlue’s sale is short-lived. Tickets must be purchased by midnight Wednesday, though JetBlue warns seats offered at the sale fares will only be offered “while supplies last.”

Meanwhile, Southwest’s 72-hour sale – one of two broad sales that carrier typically offers each year – is entering its second day.

Southwest’s latest sale has dropped round-trip fares below $100 on dozens of the carrier’s shortest routes.The sale also includes longer routes, with the price of flights loosely tied to distance. Flights begin at $49 each way on Southwest’s shortest routes and increase to $79, $99 or $129 each way for longer flights. Domestic fares included in the sale appear to top out at $154 each way.

Southwest’s sale ends Thursday at midnight Thursday.

Typically, Southwest’s rivals match its sale fares – at least selectively. That appeared to be happening on certain routes as of Wednesday morning.

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