Palma is one of the busiest airports in Europe. From April to November there are flights from many European cities. During the winter the choices of direct flights are more limited. It is though easy to connect in Barcelona. From Barcelona there are many flights every day the whole year. There are also several budget airlines that fly to Palma, especially from Scandinavia, Germany and UK.

www.spanair.com
www.sterling.com
www.blue1.com
www.ryanair.com

There are good ferry connections between Palma and Barcelona. Ferries are leaving in the morning and in the evening. The trip is taking approximately 4-7 hours (depending on ferry type) and the quality of the ferries is good. You can book a cabin or travel without it. The ferries make it easy to take your car to Mallorca if you should wish so.
www.trasmediterranea.es

By Car

Because of the frequent ferry line, it is very easy to use your own car to get to Mallorca. The car will be very useful when you are in Mallorca, since there is a lot to see. The roads are in a very good condition on the whole island. If it is cheaper to use your own car or to travel by flight and then rent your car is very much up to how long you are going to stay in Mallorca.