If it ain't broke, don't fix it. At least that's the motto of the military forces keeping these machines running.

Yes, there are indeed some operational T-34 tanks in third world countries, but good luck finding them! There are also Spitfires, and three candidates from 1957: the Lockheed U-2, the Lockheed C-130 Hercules and the Boeing KC-135 Stratotanker. But those old units didn't even make it into our top 10.

10.) Tupolev Tu-95

Introduction: 1956
Operator: Russia

Personally, the "Bear" is one of my all time favorite planes. It's a long-range turboprop nuclear bomber. Doesn't get much more badass than that. Bluecold tells you more:

The Tupolev Tu-95 Bear. Production started in 1952, same as the B52. It was put into service a year later than the B52. However, the B52 was produced from 1952 to 1962. The Bear was produced from 1952 to 1994. I think that counts for something, as does the soundtrack. I like CROR's, the Antonov An 70 made quite an impression in Paris this year.

The Russians will keep it combat ready until at least 2040...

Suggested By: Bluecold, Photo Credit: AP Images

9.) Boeing B-52 Stratofortress

Introduction: 1952
Operator: USA

America's answer to the Bear. Looks environmentally friendly, doesn't it? The government plans to keep it into service well into the 2040s which means it'll have an operational life of nearly 90 years.

Suggested By: Gamecat235, Photo Credit: Getty Images

8.) Mikoyan-Gurevich MiG-17

Introduction: 1952
Operator: Tanzania

The MiG-17 was designed to kick some American ass in the Vietnam War, and so it did. Today though, you could call it slightly outdated. Not like Tanzania is going to face off with an F22 anytime soon.

Suggested By: Gamecat235, Photo Credit: StuSeeger

7.) Antonov An-2

Introduced: 1947
Operators: North Korea

The An-2 is used as a brilliant agricultural plane all over the world. But not in North Korea! When they have enough to pay for fuel, the AN-2 is an active part of their deadly fleet...

Suggested By: Gamecat235 , Photo Credit: Dave Hamster

6.) M3 Stuart

Introduction: 1941
Operator: Paraguay

Paraguay likes to keep it old school too with some WW2 American machinery. Who could blame them? The M3 Stuart is a great choice if you're after light and agile tanks...

Suggested By: manifold engines, wanting for time, Photo Credit: PhotosNormandie

5.) BAP Almirante Grau (CLM-81)

Introduction: 1941
Operator: Peru

The Almirante Grau was originally commissioned into the Royal Netherlands Navy as De Ruyter way back in 1941, and is still in active service with the Peruvian Navy.

A bit of correction from Jod:

Technically commissioned after the war, but was launched (by the German occupation) in 41.

Suggested By: ranwhenparked, Photo Credit: Wikipedia

4.) Parnaíba (U17)

Introduction: 1937
Operator: Brazil

Brazil also has a floating museum on the river...

Suggested By: straight_six, Photo Credit: shipbucket.com/Stugger

3.) Boeing PT-17

Introduction: 1934
Operator: Mexico

Another sort of Boeing down south:

Mexican Air Force still have a few Boeing PT-17 kayoed from the 1930's. They're mostly used for air shows but are still registered as active military planes.

The Mexicans use them as trainers.

Suggested By:Kate's Dirty Sister , Photo Credit: Armchair Aviator

2.) Amerigo Vespucci

Introduction: 1931
Operator: Italy

A proud member of the Italian Navy since the thirties. Beautiful.

Suggested By: Reborn Pyrrhic, Photo Credit: Getty Images

1.) USS Constitution

Introduction: 1797
Operator: USA

'merica, 'merica, 'merica!

Suggested By:ttyymmnn, Photo Credit: Getty Images

Welcome back to Answers of the Day - our daily Jalopnik feature where we take the best ten responses from the previous day's Question of the Day and shine it up to show off. It's by you and for you, the Jalopnik readers. Enjoy!

Top Photo Credit: AP Images