You’ll find that when you are about to reserve and make a deposit on your cruise, you will have the option of purchasing a round-trip air add-on from the cruise line. While an air/sea package might avoid the hassle of finding and booking your own air ticket, be aware of the pros and cons of these convenient add-ons.
If you purchase the air/sea package, most likely your transfers between the airport and the ship will be included in the price.
It’s the ultimate convenience. The cruise line will claim your luggage for you and carry it to the ship, and all you'll have to do is board the bus.
If your flight is delayed, the cruise line will be aware of your delay and may be able to hold the ship for a few hours. If not, they will make every effort to get you to the first port to board the ship (not necessarily at the cruise line’s expense, however).
While cruise air booking has improved in recent years with added ability to choose your own flights (though somewhat limited in airline and connections), some lines (Carnival and Norwegian, for instance) remain steadfast in choosing your flights for you and only making you aware of them just weeks before you cruise.
Generally speaking, cruise/air tickets are consolidated – or bulk - tickets, purchased by the cruise lines months in advance, and carry strict rules different from published rates. Most likely, everything will go smoothly with your flight, but in the event your flights are delayed or canceled, re-ticketing or rescheduling may not result in the flights you desire.
Arranging your own flights:
If you decide to purchase your own tickets, you might be able to find a better deal, flying nonstop with an airline you prefer while earning frequent flyer miles. For instance, Southwest has awesome deals (and bags fly free!), and can only be booked through the airline directly.
Enlist the help of a travel agent, especially if you booked your cruise through one. They may be able to find the exact flight you’re looking for at a great price. An agent can be particularly helpful with complicate itineraries, using some creative ways to get you from Point A to Point B that you would not have thought of yourself.
Keep in mind the time of your ship’s departure. You’ll want to be on the first flight out of your home city, and preferably non-stop, to avoid any delay in getting to the ship. If at all possible, fly in at least a day before your cruise to allow for delays, mechanical failures or flight cancellations.
Also remember that will have to find your own transportation to the cruise terminal and claim your luggage and carry it with you. For convenience, however, cruise lines offer cruise/air transfers for independent flyers. In some cases, depending on the distance from airport to cruise ship, cruise ship transfers are worth it. If, however, you’re flying to Miami for a cruise from the same city, a taxi is quick and cheap.