Top-secret N.Korea Mission Hit by Plane Hitch

A secret mission by America's spy chief to free two U.S. citizens held by North Korea hit an embarrassing snag when his plane broke down while refueling, a U.S. official said Monday.

Director of National Intelligence James Clapper was sent to Pyongyang last week as the personal envoy of President Barack Obama to bring back detainees Kenneth Bae and Matthew Miller.

But his arrival in Pyongyang was delayed when his Pentagon plane broke down while refueling en route to the North Korean capital. 

The breakdown is the latest problem to plague the government's aging fleet of aircraft.

State Department spokeswoman Jen Psaki would not go into the specifics of the technical problems that beset Clapper's plane.

A U.S. intelligence official who spoke on condition of anonymity confirmed reports that Clapper spent the night in Hawaii while a second aircraft was sent in to fly to Pyongyang the next day.

Clapper returned to the United States in the Air Force plane on Saturday, landing at Joint Base Lewis-McChord in Washington state.

He brought home Bae and Miller, who had both served lengthy sentences in a North Korean hard-labor camp.

It's not the first time that American diplomacy has been stalled by the technical troubles of the U.S. Air Force fleet that serves the president's top deputies.

Secretary of State John Kerry has been forced to fly home commercially twice this year after his plane broke down -- once after a round-the-world trip in August, and then again in Vienna last month.

On two other occasions in 2014 -- in Switzerland and London -- Air Force aviation experts had to scramble to fix Kerry's Boeing's C-32, the military version of the Boeing 757, and get it back into the air.

"There's no question it presents technical and logistical challenges," Psaki said.

There are several planes in rotation and it was not clear if Clapper's plane was the same one that Kerry has used in the past. 

Former Pentagon chiefs in recent years have also faced delays due to technical problems with their aircraft, some of which date back decades.

The mechanical problems became so acute that officials now regularly send a C-17 cargo plane as a back-up aircraft to ensure the Pentagon chief is able to go ahead with his scheduled visits.

The defense secretary flies on one of several E4-B planes, a modified Boeing 747 designed during the Cold War to serve as a command center in a nuclear war.