Just to add to what Wubbs has shared, travel to/from the airport:
By public transport, there are two routes. Both take around one hour:
Route 1: Bus 119 from all terminals at Prague Airport to Nádraží Veleslavín metro station (line A). Then the metro to your destination in the city.
Route 2: Bus 100 from all terminals at Prague Airport to Zlicin metro station (line C ). Then the metro to your destination in the city.
Fare: 32czk if you board the bus with a ticket ; 40czk if you buy a ticket onboard the bus (exact change required).
If you're there longer than a day or so, there are options of:
1-Day Pass (24 hours) at 110czk
or
a 3-Day Pass (72 hours) at 310czk
All tickets are on sale at the Public Transport Information desk at the airport - once you come through to the public side of arrivals, its on your right hand side.
The travel ticket needs to be validated at the start of use but once done, you don’t need to again
I'm sure there will be the 'we travel without a ticket and I've never been asked etc etc' comments but the fine is far higher than the ticket - we were there the weekend before Christmas and bought the 3 day ticket .............. only time we were asked was on the return tot he airport.
You're call