Pisa Galileo Galilei Airport IATA: PSA (http://www.pisa-airport.com/) is the main airport of Tuscany and is served by several airlines operating hundreds of weekly flights to national and international destinations. Numerous companies offer charter flights to and from a number of European and non-European destinations. Flying to Pisa is really cheap and easy: the most recognized low-cost airlines serve Pisa. The airport is close to the city center - it takes only a few minutes to reach the center by bus, train or taxi. The airport is also within easy walking distance of the center, which takes around 20 min.
Do not expect the airport to be open 24/7, though. Many smaller European airports do have opening hours, so don't expect to stay overnight or hang out until late.
You can purchase bus tickets from the information desk in the arrivals hall. The bus The Red Line or LAM Rosso towards Jacobo has a regular service every 10-15 min and it takes about 15 min to get to the city. The bus runs to Piazza dei Miracoli and the central station. Since the ticket machine at the bus stop "speaks" only Italian, it's better to get the tickets from the information desk if you don't speak the language. Single fare is €1.20, but if you buy them from the driver on the bus, you pay €2.00. All convenience and book shops also sell the ticket. An automated people mover is under construction between Pisa Airport and Pisa Station which will open in 2015, in the mean time a temporary replacement bus "PisaMover" is in operation, which costs €1.30.
The bus terminal is directly in front of the airport, on the right side when coming out of the terminal building. Once you are in the city, its main sights are easy to locate and are all within walking distance. If you are boarding the bus from the Train station, cross the road in front of the station and walk a few feet to the right.
If you prefer a more convenient method of travel, a taxi to the city centre will cost around €6-8. Otherwise, as an alternative, you can book an airport transfer in advance. This service is especially convenient for large groups.
Easy Private Taxi has Pisa Airport to the city at €36 for a Mercedes E class, €43 for a minivan
123 Transfers has Pisa Airport to the city at €37.50 for a sedan 3 people, €50 for a minivan 8 people
Pisa has regular trains to and from Florence usually three per hour, to and from Lucca usually every hour and is also accessible by bus, and has an international airport.
Pisa Centrale is the main train station of Pisa. Rome to Genova trains stop at Pisa Centrale. If you are planning an in-route visit to Pisa, it is also convenient since Pisa Centrale has Left Luggage service open from 6AM-9PM. Each baggage deposited costs €3 for 12 hr. Else, if you are in the city just to see the Leaning Tower, you could also get down at the Pisa S. Rossore train station which is much closer to the Tower. Do check the train schedule as not all trains would stop there.
From Florence Firenze, catch your train from Firenze S.M. Novella station. Depending on time, there are about 4 trains per hour. Check the schedules on the now very user friendly trenitalia site. It is much improved. When possible, catch the faster and more modern "Regionale Veloce" train same price, €8.10, July 2015 - you can see this from the trenitalia schedule online. Remember the train number, as you need to match this on the departure boards at the station. The boards will not always say "Pisa" since it is not the last destination. Train tickets in Florence can be purchased from the many machines at the platform, which accept credit cards Visa/Master/AMEX - but they need to be chip/pin based. Even though the machine presents you a selection of train times, in which you need to select in order to purchase, you must still validate the tickets at the many green machines on the platform - not doing so will risk fines. Do not attempt to board without a ticket, they will check.