Over time, travel and trade made sincerity ever more important in judging the bona fides of strangers.

WSJ: Book Review: Sincerity

And like commercial aviation, Wincer predicts that the price of space travel will go down over time, as the efficiencies improve and research costs are spread over more passengers.

FORBES: Out Of This World: Space, The Final Frontier

Their stories are part of a new series of conversations about air travel today and how it has changed over time.

NPR: Air Travelers Say Hassles Mount

"With TSA staffing levels decreasing over time, we expect that during busy travel periods wait times exceeding 30-40 minutes could double at nearly all of the largest airports, " the TSA said in a statement.

CNN: Longer lines at airports due to budget cuts?

Summer is almost over, so now is the time to work out those last minute travel plans.

FORBES: How Foreign Transaction Fees Cost You

Of particular note is the observation by Airbus engineers that by optimizing technology (much of which is available now), flights in Europe and the U.S. could reduce per-trip flight time by 13 minutes, which worldwide would save approximately nine million tons of fuel annually, avoid over 28 million tons of CO2 emissions and cut five million hours from travel time aloft.

FORBES: The Agony and Ecstasy Of NextGen: The Air Traffic Control System Of The Future

The single biggest advantage of train travel is that it goes from city center to city center, without the need to arrive over an hour early, which in many cases can save you 2-3 hours of travel time (and taxi expenses) before you even count the travel itself.

FORBES: Don't Fly - Why Trains Are the Best Way to Travel Overseas

Under EU law, inhabitants of the Union are allowed to travel freely between each country, a privilege that has been a long time coming all over Europe.

FORBES: British Plan To Keep Greeks Out, As Euro-Crisis Nears End Game

One of the largest of them, the USS Abraham Lincoln (which I visited in April), weighs almost 100, 000 tons, has a full-time crew of about 5, 000 (including its permanent air wing) and can travel over 30 knots per hour.

FORBES: Fact And Comment