Another 22% of the cost increase has resulted from delays in development of the F135 engine that will power the fighter.

FORBES: Super-Weapon: Why Have F-35 Fighter Costs Increased?

They have also made possible the development of totally integrated power systems, which make energy fungible: instead of having one engine dedicated to driving the ship and another one devoted to generating shipboard power, electricity from multiple sources can simply be routed to wherever it is needed at the time.

ECONOMIST: Electric ships

The trend towards more twin-engined aircraft drives up the cost of engine development, by boosting the need for power and reliability.

ECONOMIST: Aircraft engines