Flexjet is offering new and existing customers free fuel when they purchase fractional shares from now until April 30. Customers purchasing a one-sixteenth share in a Learjet will receive a credit of 12 hours of free fuel; a similar share in a Challenger earns a 25-hour fuel credit. According to Flexjet, the credit, which includes fuel component adjustments and federal excise taxes, is based on published rates on the day of contract closing and will be applied to the fuel surcharges per hour flown.