There's no train connection with Acapulco Airport.
Car and bus
Acapulco Airport is situated 19 kilometers southeast of the city center. The airport is easily accessible by rental car. From Acapulco center you drive along Acapulco Bay to the Boulevard de las Naciones which leads to the airport.
Outside the Arrivals Hall you can find a minivan of Servicio Colectivo. It leaves every 10 minutes and runs along the most popular hotels. Transportes Terrestres' shuttle bus is cheaper (Tel. +52(0)744 462 1095).
Car rental Acapulco Airport
You can find counters of car rental companies in the Arrivals Hall. Six rental companies are present at Acapulco Airport: Alamo, Avis, Budget, Europcar, Hertz and Thrifty. You can also book a rental car in advance using the service provided by EasyTerra; they compare the rates of several providers in a single quote.
A taxi ride to the popular hotels along the beach takes about 30 minutes and costs US$ 20-25 (the official currency in Mexico is the peso, but taxi drivers also accept US$).
There's a parking lot outside the terminal. You pay 28 pesos for the first hour, and then 7 pesos per 15 minutes with a maximum of 240 pesos per day.