It's already several decades ago that I stood next to a professor of aerodynamics at a European Air Show, waiting for some (still Soviet) Russian helicopter to be demonstrated. We had been informed that the "Commie Moulinex" would show some hitherto unseen manoeuvres, and we weren't disappointed! Right before our fascinated eyes the pilot took his helicopter (I reckon it was the then newest Bolkow) through a couple of perfect loops, which indeed we had never before seen any rotorwing do. Not intentionally, that is (wide grin)!

We sighed contentedly, and the professor softly spoke: "Jaap, only a few years ago most aerodynamicists, including myself, would staunchly maintain that helicopters can't fly loops. Today I've been proven wrong. That's not the first time, nor will it be the last. Mark my words, young Jaap: in your very lifetime you'll see many more developments in aviation that we now consider impossible."

My tame scientist has been dead now for many years, but I still remember his words. Statistically, I have another twenty years to go before I croak (I'm 63 at the moment of writing), and not only am I still fascinated by all that's happening in aviation, but I'm also eagerly looking forward to all the wonderful future things that I will be witness of!