Snag $19 flights on Frontier Airlines during this quick sale

For those eyeing late-summer and fall trips, Frontier Airlines is offering airfare for as low as $19 this week, but travelers must act fast.

The Denver-based low-cost carrier launched an airfare sale for trips through Oct. 7 on Tuesday that ends Thursday at 11:59 p.m. ET. Two million seats are on sale, according to the carrier.

Deals out of Boston include $19 to Charlotte, Raleigh, Cincinatti, and Philadelphia; $49 to Orlando; $69 to Dallas; and $89 to San Juan.

The discount fares are valid for nonstop travel on Monday through Thursday, and also on Saturday. Tickets must be purchased at least seven days before the trip and blackout dates are Aug. 29 and Sept. 2-3. There are exceptions for Las Vegas, Florida, and international travel, which are detailed on the company’s website.

What’s more, travelers can enter a sweepstakes to win 1 million Frontier miles — enough for as many as 100 flights, according to the carrier. Travelers must enter by Thursday and the winner will be determined through a random drawing. Sweepstakes entrants must be members of the Frontier Miles Program, which is free.

“These miles can be used on flights to destinations across the country, the Caribbean, and beyond, and will mean countless memories for our lucky winner and the people close to them!” said Tyri Squyres, vice president of marketing for Frontier Airlines, in a statement.

In May, Frontier announced The New Frontier, featuring transparent pricing and no change or cancel fees.

Tickets can be purchased at flyfrontier.com.