Courtesy of ERIC SALARD/Flickr

Norwegian promised, and it delivered. Today it launched its highly anticipated $65 flights to Europe, which will begin this summer, after the airline gets its first delivery of narrow-body Boeing 737-MAX aircraft. Now, if you think it might be too good to be true, you’re sort of right. There are lots of caveats about these fares, but at the end of the day, you really can’t beat the deal, and it’s absolutely worth it to book (which you can do here). We previously discussed the strict rules of discount flights when WOW, an Icelandic budget airline, offered $69 trans-Atlantic flights, so you might want to read up on baggage restrictions, entertainment offerings, and more. But here, we’re clearing up a few things about this specific Norwegian deal.

1. The $65 flights are one-way.

We mentioned this in our WOW article, and we’ll mention it again here. To reiterate: $65 is for one leg of the flight only. (In this case, the U.S. to Europe leg.) That being said, Norwegian is offering return legs for as low as $80.20, meaning your round-trip booking could cost as little as $145.20, which is an incredible steal.

2. The deal is only for Norwegian’s new routes, which are from two small U.S. airports to the U.K. and Ireland.

Norwegian might market its new routes as departing from New York City or Boston, but, in fact, neither of its U.S. airports are in those cities. To keep costs low, the carrier will fly out of the smaller airports of Stewart International Airport in New Windsor, New York, and T.F. Green Airport in Providence, Rhode Island. (Note: In the future, Norwegian will also fly these routes out of Bradley International Airport in Windsor Locks, Connecticut.) Keep in mind that these airports are much farther away than the main airports in NYC and Boston—a trip to Newburgh from Manhattan takes some two hours on public transportation. Additionally, the $65 fares only apply to specific destinations in the U.K and Ireland: Edinburgh, Belfast, Dublin, Shannon, and Cork.

3. They’re almost entirely sold out.

There are very limited quantities of the $65 fares, and since they’ve been available for a few hours (at the time of publishing), many discounted tickets have been snatched up. Don’t keep your hopes up for the release of more—the cheap flights are only an introductory promotion. Luckily, regular fares will only be slightly more expensive. Norwegian’s base ticket price on these routes will be $99 from the U.S. to Europe, and the return leg will be €99 or £99.

What You Need to Know About Those $69 Flights to EuropeThe 10 Best Airlines for Those of Us Flying Coach6 Tricks from a Flight Attendant That Will Make Your Trip Easier