I think the concept is brilliant, but how does it scale out? So, they implement this at major airport and then what? The whole model is predicated on the fact that you
know your car is being unused because you are physically incapable of accessing it.
So let's think of scenarios - you park your car for the day for work so you rent it out. What happens when there is a emergency, or you need to pop out for a quick errand? What happens when the person returning it shows up late? The reason you buy a car is for the convenience to be able to transport yourself from A to B, at any point that you need to. I just see so few scenarios, except for traveling out of your home location, that could warrant this model scaling out to other scenarios. The number of airports is very static too.
Personally, I would much rather see good public transport take off in over congested cities like SFO, NYC, etc. I see a business model like this as fixing the wrong problem.
Assuming they reduce all of the liabilities (which is 100x harder to do with mechanical items as opposed to an apartment/house) then I definitely see this taking off. On the flip side, I suspect margins will forever be razor thin in order to be competitive and the growth will halt when no new scenarios beyond airport parking can be found.