Rovaniemi suits a Lapland base. Keep the first drive short and check child-seat fit before leaving the airport.
Finavia provides the airport’s car-rental listings. Confirm the collection appointment and flight details with the company; do not rely on an unbooked desk being staffed for every flight.
A car is useful for rural lake accommodation, national-park approaches and independent travel beyond the main train routes. Helsinki city days often work better before collection. Lapland is a separate regional choice, especially in winter.
Compare airport collection with a later collection if you start with a city stay. Include the transport to a different rental branch and any extra parking nights when comparing the total cost.