@NexusOoi @devchart A suburb in Austin has this.
For direct answer your question, land at a GA airport in the city they want to go for the day, and most of the FBOs of any size have cars on site (gorentals.com) that people can rent for the day. 
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@NexusOoi @devchart The grocery store or CFA comment might be hyperbole (or not?) b/c I wouldn’t do all that for a chicken sandwich, but the idea of flying into a city for a day of shopping, then flying home? Not in my budget, but people do it.