If the contractor is considered as an employee of the company, it is better that the company pay mileage since employee business expenses are no longer deductible under the new tax laws.
If it's his company, it doesn't really matter tax-wise which option you choose. From the point of cash flow for the contractor, I would think he'd prefer having payments reimbursing him throughout the year.
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"