What can $4,367 buy? For one NASA employee, it bought a business-class flight from Frankfurt, Germany, to Vienna, Austria. Coach-class fare for the same flight was $39.

The federal government spent millions of dollars on thousands of upgraded flights for employees in 2012 and 2013, paying many times more for business and first-class seats than the same flights would have cost in coach or the government-contracted rate.

Premium travel reports from 14 federal agencies documenting the flights show these agencies alone spent an estimated $8.7 million on 1,903 upgraded flights in those two years. That was about $6.4 million more than the same coach and government-rate flights would have cost.

The agencies spent $5.7 million in 2012, almost double the $3 million they paid for premium travel in 2013.

The cost of coach and government-rate flights is approximate because several agencies either reported estimates for some coach fare or didn't report them at all.

Agencies report their premium travel expenses to the General Services Administration each year. These reports were obtained by the Washington Examiner through Freedom of Information Act requests.

The federal government contracts with airlines for specific carriers and prices that are mandatory when available, a Labor Department spokesman said.

Exceptions for business or first class are made for specific criteria.

The most common reasons across agencies for such "premium" flights in 2012 and 2013 were medical necessities and flights with more than 14 hours of travel time.

Other reasons include special security risks, no coach flights available within 24 hours of arrival or departure time, overall cost savings, unsanitary coach accommodations on a foreign carrier, and a vague exception for upgrades "required for agency mission."

The Defense Department topped the 14 agencies, paying about $4.5 million for 784 flights, compared to the $3.1 million cost of the same coach flights.

The most commonly claimed exception for DOD flights was "required for agency mission," according to the DOD report.

One such flight was a trip from Washington, D.C., to Brussels, Belgium, which cost $6,612 instead of $863.

Similar mission-required upgrades included several flights to Kuwait for $6,911 instead of $1,471, a flight from D.C. to Tokyo for $7,234 instead of $1,081 and a trip from D.C. to Paris for $6,037 instead of $477.

Some flights were predictably expensive because agencies like the Departments of Defense and Commerce and the Securities and Exchange Commission frequently have official business outside the U.S.

Commerce Department employees trailed only those at DOD among the 14 agencies, paying almost $2.3 million for 635 flights.

Other agencies' international flights were less predictable. Department of the Interior employees, for example, flew to such exotic locations as Costa Rica, Denmark, Japan and South Africa in 2012.

Then-Interior Secretary Ken Salazar took an April 2012 trip to Brazil for a "special agency mission" that cost more than $3,800 each way instead of the $3,000 coach fare round-trip.

NASA employees also racked up a long list of flights that cost 26, 72 and even 112 times the cost of coach fares, according to Examiner calculations.

Several space agency employees flew from Oslo, Norway, to Tromso, Norway -- a trip that should have cost $65. Instead, each flew business class for $4,668.

Another NASA employee flew from Frankfurt, Germany, to Cologne, Germany, for $6,851 instead of $133, a flight that cost almost 52 times more than the coach fare.

NASA withheld reasons for its flight upgrades in the report released to the Examiner.

The Department of Labor sent employees to places like Vietnam and the Philippines for "informational meetings," conferences and site visits.

One flight from D.C. to Hanoi, Vietnam, for an informational meeting cost $15,529 instead of $1,649, according to the agency's 2012 report.

Most of the department's international flights are for Bureau of International Labor Affairs employees, which "leads the U.S. Department of Labor's efforts to ensure that workers around the world are treated fairly and are able to share in the benefits of the global economy," a spokesman told the Examiner.

These efforts include representing the U.S. at the G-20 summit and bilateral discussions, and working to prevent child exploitation overseas.

Many of the agencies spent less in 2013 than in 2012, but upgraded flights still cost millions each year.

“Paying $12,000 for a flight is the likely the result of poor planning and not booking flights until the last minute. Even so, it's hard to justify that kind of travel expense, particularly to exotic destinations, in the age of video conferencing," John Hart, a spokesman for waste watchdog Sen. Tom Coburn, told the Examiner.

The real question these reports raise is whether agencies are monitoring premium travel and what kind of transparency they enforce for why employees are booking the more expensive flights, said Tom Schatz, president of Citizens Against Government Waste.

“From the taxpayer's point of view, everything should be done to avoid the use of first-class travel unless absolutely necessary," Schatz said.