Beware the Middle Seat

I recently booked a flight with Travelocity (http://www.travelocity.com) and found that I had a choice of seats on the second leg of my flight. However, all the choices were middle seats. Several years ago seats booked through Travelocity or its competitors seemed usually to be at the very back of the plane. I don't know whether the middle seat thing is common now, but I'm willing to put up with it for savings on flights.
On this trip I changed at DCA, otherwise known as Reagan National Airport in Washington DC. In Montreal if you are flying to this airport you use a special gate, and a security official came in and told everyone to leave while she "secured the area." I'm not sure how she did this (there was opaque glass blocking my view,) but she was holding a long metal implement with a mirror on one end of it, similar to the instruments border guards in the Soviet Union used to put underneath vehicles entering or leaving that country by land borders. They apparently did this to check for bombs or stowaways (though I don't think there were many people then trying to sneak in.) Today, with the rise of the national security state it isn't just in totalitarian regimes where one encounters walls taller than the one that used to divide Berlin--think Israel and Palestine, or the U.S. and Mexico.
On the bright side of this trip, this time there was no requirement to stay seated for an hour before landing, as there was for a while after 9/11 on flights into Reagan. This flight was lovely, right over leafy northwest Washington and Georgetown, my old 'hood, along the sparkling Potomac past the Washington and Jefferson memorials and onto the runway.