The MiG-21 is one of history’s sturdiest and most reliable aircraft..
Military aircraft can have notoriously short lifespans, especially during periods of technological ferment.
The most elite aircraft of World War I could become obsolete in a matter of months.
Things weren’t much different in World War II.
And at the dawn of the jet age, entire fleets of aircraft became passé as technologies matured.
The advanced fighters that fought in the skies over…
Source: Could Russia’s Cold War Super-Jet Last 100 Years? | The National Interest