When you book a car rental through Alternative Airlines, you will still be required to pay a security deposit via a credit card.
A security deposit is a charge placed on your card when you collect your vehicle. The charge is in a "hold" state, instead of the money fully leaving your account. The security deposit charge is then released when you return your vehicle.
If you return your car with damage, excess dirt etc the car rental supplier may charge you from this deposit amount.
Security deposit amounts can vary by supplier; please check your rental agreement terms and conditions before purchase for more information.