Both Cost Plus Award Fee and Cost Plus Incentive Fee contract types are Cost Reimbursable contracts in which the seller is reimbursed for completed work plus a fee representing profit.
In the PMBOK guide, for Cost Plus Award Fee contract below point is mentioned,
The determination of fee is based solely on the subjective determination of seller performance by the buyer, and is generally not subject to appeals
And for the Cost Plus Incentive Fee contract below explanation,
The seller is reimbursed for all allowable costs for performing the contract work and receives a predetermined incentive fee based upon achieving certain performance objectives as set forth in the contract
Are there any other differences between these 2 types of contract?