41 C.F.R. § 301-70.905 – Documentation retention.

(a) Agencies must retain for two years copies of travel authorizations for senior Federal officials and non-Federal travelers who travel on the agency's Government aircraft.
(b) Agencies must also retain for two years the following information for each flight:
1. (1) The tail number of the Government aircraft used.
2. (2) The dates used for travel.
3. (3) The name(s) of pilot(s), other crewmembers, and qualified non-crewmembers.
4. (4) The purpose(s) of the flight.
5. (5) The route(s) flown.
6. (6) The names of all passengers.