If it is within one small country, then of course it is a car, but if it is a journey from Poland to Portugal, it can take a long time, in which case it is preferable to travel by plane. But plus to go by car - you can take a little more things and parcels with you. The other day I got myself a virtual mailing address in the USA (check more details at the https://getnewmailbox.com), and now the parcels come there, and accordingly, they can be sent to me from there to Europe, where I calmly pick them up.
In absolute numbers, driving is more dangerous, with more than 5 million accidents compared to 20 accidents in flying. A more direct comparison per 100 million miles pits driving's 1.27 fatalities and 80 injuries against flying's lack of deaths and almost no injuries, which again shows air travel to be safer. Click here for details: https://xmudderwheel.com/off-road/rim-size/20-inch/