This would be great! This is where people still hire cabs in my city--If you have an early flight, do you trust that there will be an Uber driver available? Or do you pay a little extra and call a cab service with a scheduled pickup?
The difficulty is that there's still no guarantee that an Uber would be available. It'd just take care of the request part. Would need to be some thinking around what if there's none available in the area etc.