The simplest way to get from one place to another in Morocco, is to use Royal Air Maroc, who fly several times a day between the main cities, and offer a good value service. Supporting this, Morocco's rail network is one of the most modern in African, and covers the north of the country. For journeys going a bit more off the beaten track, there are usually taxis available in city centres and at hotels, which have standardised fares to many destinations within the country.
Hiring a car in Morocco is a good idea if you are planning to explore the country, but not such a good plan if you are keeping to the crowded city centres.