I take up to 10-12 flights every year. I absolutely love the experience of flying, even when it is economy class or on a low-cost airline. I was wondering though: how long are we going to have the luxury of cheap international travel? Estimates about how soon crude oil is going to run out vary wildly, although I think pretty much everyone agrees that within the next, say, 30-40 years it is going to get more expensive due to fuel shortages. It already is getting expensive. While surface transportation will probably survive in the form of biofuel or electric-powered cars, what we have absolutely no replacement for is a way to power commercial passenger planes or ships!
Think about it. Petroleum fuel-powered engines are the only viable means of powering flight at the moment. Point is, at the moment research and production of alternative means of powering transportation is simply not economically lucrative. Maybe it would need crunch-time pressure as we near the end of oil reserves to make companies sit up and work their research departments towards this. At the moment, battery technology isn’t anywhere close. The only alternative, long-term resource we have is nuclear power, and even those engines are primarily steam engines – good for slow-release engines on ships but not for the intensive take-off / landing cycles of airplanes. Nuclear technology is so strictly controlled and has so much potential for mishaps that I cannot imagine it being used in the commercial sector anyway.
So maybe humankind will figure something out in the next few decades. But what if. What if it isn’t realistically possible to make an engine that can give the performance of an internal combustion engine or jet engines? How different the world would rapidly change, back to the days when seafaring nations controlled the balance of power! Back to the days when journeys took weeks and months! Back to the days when it won’t be possible to buy 10 pence bananas flown in from Africa in a supermarket in England, or buy cheap electronic gadgets on eBay from Hong Kong! I don’t reckon producing electricity will be a problem; even if we have to gag and lock up protesting hippies, hydroelectric power could potentially fill in a major part of the shortfall. But perhaps within the next five decades, we may never ever again be able to fly to any part of the globe in less than a day.