Even though Varadero is only a small town, its airport is the second busiest in the country thanks to the constant flow of tourists traveling to Varadero, mostly from Canada and Europe. The airport is not very big, but it's filled with small souvenir/duty free shops so you can easily spend those last few pesos while waiting for your flight - and since Cuban currency cannot be exchanged outside of Cuba, unless you plan on going back, it's better to spend it on a bottle of rum than to be stuck with it. Another thing to keep in mind is that you will need to pay a 25 CUC departure tax when you leave (to be paid in cash). Security isn't very tight when you leave (my friend had two bottles of rum in her carry-on luggage and they let her through so the 100 ml rule for liquids doesn't seem to apply), but they can be a bit fussy when you arrive, especially when it comes to electronics. If you have booked an all-inclusive resort, you will see plenty of buses waiting outside the airport and these offer free transportation to most hotels - someone will let you know which bus you should get on as they have a list with the names of all travelers. Otherwise, you will also see plenty of taxis waiting next to the free shuttles - just make sure you agree on the price before you get in. The ride to Varadero takes about 30-45 minutes, depending on how far from town your hotel is located. And while you're waiting for the shuttle to depart, why not have your first Cuban beer? They sell cold Cristals, which you can pay for using any currency - apparently prices vary, but we paid $5 for 2 deliciously refreshing beers!
The airport closest to Varadero is Juan Gualberto Gómez International Airport. There are direct flights and charter flights from Canada, Central America, Europe, South America and Africa. It's a small airport with 2 or 3 small shops, 2 cafeterias, internet access and money exchange.
Keep in mind that you need to pay a departure tax of 25 CUC when leaving Cuba.
If you are going to the airport by (rental) car, make sure you have 2 CUC available for the road toll.
From the airport to the hotl stip is a 15 miute ride. From there it depends where your hotel is, so you'll be 15-20 minutes away.
Taxi cost is 10-15 usd, but most hotel packages include a bus ride to your hotel.