This message cannot be received in error and only will occur if any app including Infinite Flight has been refunded at any time. Repurchasing Infinite Flight would be required in this scenario.
Another possibility that could generate this error would be if you had previously purchased Infinite Flight with a different iTunes account. In this case sign out of the account with this error, and then sign back in with the iTunes account associated with the original purchase.
If you believe there is some mistake, please contact your iTunes app store for account assistance.