The government can save significant funds by purchasing normal, non-refundable airline tickets. Presently, fully refundable and changeable tickets are purchased at premium prices in order to allow for full refund and/or easy changes.
However, these tickets may be 3-4 times more expensive than the same non-refundable ticket. Some airlines merely charge a nominal fee ($100 perhaps) for cancelling tickets and issue a credit for the remainder to be used in the future. Change fees are greater but would not approach the fully refundable cost for frequent travelers.
The cost savings between the change/cancellation fee and the premium paid for fully refundable/changable tickets, when considered government-wide, is significant.
This cost-savings should be captured by requiring the purchase of standard non-refundable tickets only for official travel.