In those cases, which included visits to Fort Campbell, Ky., Barksdale Air Force Base, La., Camp Pendleton, Calif., and Fort Bliss, Texas, he pays only part of the trip.
According to the formula, he essentially reimburses the government for the difference between the cost of the full trip minus the cost of flying directly to the base or official event location and back to Washington.
Little said the Friday trips are not planned to mesh with Panetta's travel to California. Instead, he said, travel on Fridays or Mondays allow Panetta to "maximize his time in light of regularly scheduled meetings in Washington."
Typically, Panetta flies on an Air Force C-37 — somewhat comparable to a Gulfstream jet — which is the lowest-cost aircraft that can carry the necessary communications equipment. In contrast, the Air Force E-4B, the "doomsday plane" Panetta uses for overseas travel because it can refuel in flight, accommodate secure video conferences and serve as an airborne command post, costs about $70,000 per flight hour to operate.
The requirement that all travel — official and personal — by a defense secretary be conducted on military aircraft was instituted during the George W. Bush administration in 2001.