Orlando International Airport is 9 miles (14km) southeast of downtown Orlando and 22 miles (35km) northeast of Walt Disney World. A decent bus service exists between the airport and downtown Orlando's Lynx Bus Center.
There are a handful of car rental companies at the airport and many more downtown. Although driving within the city of Orlando can be complicated - most streets are one-way and ticket-happy meter maids lie in wait - the area requires a car since it can be difficult to travel outside of Orlando relying on public transport. To get to Disney World from the airport by car, take Highway 417 to Highway 536, which runs right to the park. From downtown Orlando, take I-4 south. If renting a car is not an option, there's a bus every two hours from Orlando's Lynx Bus Center.
Orlando runs a highly efficient and inexpensive city bus system, including a free downtown circuit. Pick up schedules and route maps at the Lynx Bus Center. Taxis cannot be hailed on the street; you'll have to phone to secure one.