Lovers of Cabernet Sauvignon, Merlot, and Pinot Noir may want to raise a glass for Southwest Airlines.

On Monday, November 2, Dallas-based Southwest expanded its Sip and Ship program to Houston's Hobby Airport and three other Texas airports, enabling travelers to check qualifying bottles of wine at no extra cost.

The program already served 19 airports in California, Idaho, Oregon, and Washington. Now, Sip and Ship enables flyers to check one case of vino for free on flights from 23 U.S. participating airports. To ship more than one case, a traveler must pay a checked-bag fee.

In addition to Hobby Airport, Southwest added Austin-Bergstrom International Airport, Dallas Love Field, and San Antonio International Airport to Sip and Ship.

A Southwest spokesperson said the airline introduced the program at the four Texas airports “following an overwhelming response from Texas wine lovers and growers.”

With the Texas airports included, Sip and Ship allows travelers to transport vino from wine regions in five states. This means a passenger could pack a case of Cabernet Sauvignon from Northern California’s Napa Valley, Pinot Noir from Oregon’s Willamette Valley, or dry Rosé from the Texas Hill Country.

So, how does the program work?

Southwest says a traveler can ship one packaged case of wine — up to 12 bottles — weighing 50 pounds or less and adhering to size limits (up to 62 inches, counting length, width and height).

The container holding the vino must be a single box or a special wine suitcase.

Additional leak-proof packaging is required to prevent breakage. This includes packing materials such as Styrofoam, molded foam inserts, cardboard liners, bubble wrap, and extra padding for glass bottles. The airline sells padded wine bags for $5 per bottle.

Then, a Southwest agent at the check-in counter inspects the case to ensure it’s properly packed, and seals and labels the wine box or suitcase.

Once passengers arrive at their destination, they can pick up the case at baggage claim or the area for oversized baggage.

To take advantage of Sip and Ship, travelers must be departing from one of the program’s 23 airports, be traveling within the U.S., and be at least 21 years old. The program applies to connecting flights as long as the person is flying within the U.S.