Gibbs, apparently, is known for their amphibious vehicles. Check out this soon to marketed little number. 45+mph on land and water, with a conversion to either in a matter of seconds. The price is a bit up there coming in at around $40,000. Perhaps it won't be long until ATV's are allowed on the roadway in most states. At present, that seems to be a problem.
Folks, we still don't have flying cars, but this seems to be a step in the right directly. The bonus is that those on the US market will be manufactured right here in the States (Auburn Hills, Michigan).