How many of us have been jostled and crammed into a tiny airplane seat recently, only to lament delays caused by weather, extra fees demanded by the airlines for overweight bags, or the tiny bag of pretzels that have replaced meals on so many flights?  It seems like the collective mood on airplanes is pretty grumpy these days. 

But imagine what our ancestors just a few generations ago would have said if we could tell them about our ability to fly from city to city with su…