Four turbofan jet engines, with afterburners, are each able to provide more than 30, 000-lbs of thrust.

BBC: Profile: B-1 bomber

Unlike a conventional turbofan, it uses a gearbox rather than a shaft between the fan and the turbine.

ECONOMIST: Monitor

But the geared turbofan and the open rotor are so different from each other that they will need different airframes.

ECONOMIST: Monitor

That means shareholders have already absorbed the entire expense of developing the geared turbofan and can immediately begin enjoying the dividends.

FORBES: The Billion-Dollar Bet On Jet Tech That's Making Flying More Efficient

Both BA and KLM, after all, had direct experience of what flying through volcanic ash can do to a high-bypass turbofan jet engine.

ECONOMIST: The effect on business and leisure

There are actually brave souls around the world who build and fly their own jetpacks, most notably Yves Rossy, a Swiss pilot who created a flying wing powered by four small turbofan engines.

WSJ: Jetlev R200 Jetpack: Personal Flight, Beyond Bond

Turbines run most efficiently at high speeds, and fans at low speeds, so turbofan engines have to compromise between the two, because the engine's design requires them to turn at the same speed.

ECONOMIST: Monitor

The geared turbofan has put Pratt in the enviable position of supplying the most power plants for the most popular airliners for the next couple of decades: single-aisle jets that will absorb much of the travel boom in emerging markets.

FORBES: The Billion-Dollar Bet On Jet Tech That's Making Flying More Efficient

The acquisition of Goodrich in calendar year 2012, coupled with several wins thanks to their ingenious new PurePower Geared Turbofan engine, lead me to believe that United Technology Inc is poised for accelerated future growth above recent recessionary related historical norms.

FORBES: United Technologies Has Transitioned Itself For Accelerated Growth