Main airline: 3.92 years

Second airline: 3.64 years

While I try to scrap my aircraft at around 10 years old, it can be hard to find replacements for some of them.

Smaller aircraft tend to be less profitable due to several reasons:

1: Higher employee costs: You can't pay your regional airliner crews less even though they make less money than larger aircraft.

2: Blue (connecting) passengers: Unless you are operating a regional airliner between very small airports without a hub, its more profitable to use a 737 or A320 rather than a B1900 or a DHC6 since connecting passengers will fill up the excess seats.

3: Slots: A small aircraft will have to fly the same trip multiple times to carry the same amount of passengers as a larger aircraft which means that you'll use more slots.

I use a 3 star scam IFS to make low demand regional routes profitable and base the airline in a smaller Middle Eastern city (As long as its not Dubai, too much competition) which will provide me with a central location for a hub and spoke stategy. Most African, European and Asian cities are within the range of DC-8s while 747SPs can reach Oceania and South America. I also try not to operate planes that are older than 10 years to keep the maintenance costs low and scrap unused airplanes rather than sell them to the used maket so they won't be used by other airlines.