International and domestic flights to Pune(PNQ), land at Chhatrapati Sambhaji Raje International Airport. If flying in internationally, you can also take a flight to Mumbai(BOM) and then reach Pune in 2 to 4 hours via road(bus fare ~500 INR). If flying in from South East Asia, Hyderabad(HYD) may be a viable option. Goa(GOI), Bengaluru(BLR) and Chennai(MAA) airports are other options for international travellers to fly into India.
Buses from other states in India arrive at the Swargate Bus Station. Most of the inter-Maharashtra buses also arrive at this station or at Pune Railway Station Bus Stand. Visit MSRTC website for online booking.
Pune is very well connected to rest of India by trains. All trains arrive at Pune Junction railway station. Visit IRCTC website for online booking.
From Mumbai, you can get a share taxi(~600 INR) or a private cab(~2500 INR) to Pune. These take about the same amount of time as a bus.