Summer flight sales have begun, and while it may be hard to believe, the booking season is ready to take off. Major airlines like US Airways, AirTran, United Airlines, and Delta Air Lines have announced discounts over a wide range of travel days this summer, so if you’re already dreaming of hot destinations to spend your summer vacation in, pay attention to each airline’s specific discounts and start booking.

The catch? In most cases, you have to book by Thursday night at midnight. It’s the first big summer sale of the year, and it’s going fast, says USA Today.

A few examples include AirTran, which is offering flights from $44, and does not require a round-trip purchase.US Airways is having a special air and three nights package to Las Vegas that includes two show tickets and United Airlines’ Hawaiian Getaway sale offers one-way tickets to Hawaii from $295.

Cheaper prices may be harder to find for flights in July, or flights from coast to coast, so if you’re in the mood to dig, it’s a good idea to be flexible with your schedule and be willing to travel to a smaller regional airport to offset some of the cost.

Most of these fares require a ten-day advance purchase, but with a travel window of almost 200 days, there’s surely something worth finding.