[AdamJacobMuller]

It's very easy to run emergency backup generators in parallel.

Take your total load (10MW) divide by 5 (2MW) and you need 5 2MW generators, buy 7 and run 6/7 and your "down for yearly maintenance" generator can be offline while your "oh shit we installed the wrong fuel filter and the injectors clogged" generator also fails.

Much harder in a plane.

[lazide]

Especially since rarely does anyone care about how heavy the emergency generators are. But if you add 100 lbs too much in the wrong place on a GA plane, everyone is almost certainly going to die.