These are also known as Aircraft Charter companies.
Image Credit: https://www.aopa.org
For domestic travel you can take the ever popular Beechcraft King Air turboprops.
Image Credit: https://upload.wikimedia.orgFor businessmen in a hurry, there are several helicopters available for charter. You have the Eurocopter Ecureuil and Dauphin, the Bell, Agusta or McDonnell-Hughes 500 helicopters.