301-71.202—May we pay a claim when an employee does not include a copy of the corresponding authorization?

Yes, as long as the travel claim was signed by the approving/authorizing official, except for the following, which require advance authorization:

(a) Use of reduced fares for group or charter arrangements;

(b) Payment of a reduced rate of per diem for subsistence expenses;

(d) Travel expenses related to attendance at a conference.

CFR