You might be surprised. I'm about 70 miles from our airport and the break-even really is around 10 days, with how airport parking prices have gone up in the last few years. Sometimes I do still drive for convenience, with odd-hours departures or returns, or because fenced, monitored airport parking is probably a safer place for my car than on the street in front of my house if we're all away, but I was surprised that a car service wasn't more expensive given the distance and the lack of competition (no Uber/Lyft or cabs out here, so scheduled service is the only option).