To help ensure that Government aircraft are the most cost-effective alternative for travel, your aircraft management office must calculate the cost of a trip on your aircraft, whether Federal aircraft or CAS aircraft, and submit that information to the traveler's designated travel-approving official upon request. The designated travel-approving official must use that information to compare the cost of using Government aircraft with the cost of scheduled commercial airline service and the cost of using other available modes of transportation. When you operate a Government aircraft to fulfill a non-travel related governmental function or for required use travel, using any space available for passengers on official travel is presumed to result in cost savings. For guidance on how and when to calculate the cost of a trip on Government aircraft, see the “U.S. Government Aircraft Cost Accounting Guide,” published by the Aircraft Management Policy Division (MTA), General Services Administration, 1800 F Street, N.W., Washington, DC, 20405.