Prague has no rail link to its airport, so every option is a bus or a car. The cheapest route is one ticket covering a trolleybus and the metro, but the route number changed in 2024 and most published guides still print the old one, which is how visitors end up at the wrong stop.
Prague is compact enough that crowds rather than distance are the constraint, and the difference between a good visit and a frustrating one is mostly timing. What three days covers, why the castle takes longer than expected, and the exchange booth trap that costs visitors real money.
