A well-maintained aircraft can last much longer than one that is poorly maintained. Aircraft Type; Different types of aircraft have different lifespans. For example, a Boeing 747 has a lifespan of around 25 years, while a Boeing 737 has a lifespan of around 20 years.

A Boeing 737 typically has an operational lifespan of 20 to 30 years, but its longevity is measured more accurately in "flight cycles" and "flight hours" than in calendar years. Most 737 models are designed for approximately 75,000 flight cycles (one cycle equals one takeoff and landing). Because the 737 is a "short-haul" aircraft that often flies multiple legs a day, it tends to reach its cycle limit faster than a "long-haul" jet like a 777. For example, a 737 flying six flights a day would reach its 75,000-cycle limit in about 34 years. In 2026, many older 737-800 "Next Generation" aircraft are hitting the 20-year mark and being retired from passenger service, only to be converted into freighters (737-800BCF). These converted cargo planes can often fly for another 10 to 15 years because cargo operations usually involve fewer daily cycles than passenger service. With meticulous maintenance and regular "D-checks" (where the plane is essentially taken apart and put back together), a 737 can remain safe and airworthy for over four decades, as seen with some "Classic" 737-200 models still flying in remote regions today.