Go to DNC.org since they’re the ones with the most private jets, causing the most ecological damage!
If you charter a jet from a company, a pilot (and often a flight attendant!) is / are included in the price =]
When you charter an aircraft they pilots are already working for the 135 operator that holds the certificate for that particular aircraft. If you want to charter and aircraft you can go to a broker like Jets.com they have all the information you need there.