The Postcard Airplane (Aeroplane?) is a literal take on the old Aerogram – except the recipient gets the joy of making their own balsa wood plane. It's easy to write on and comes with its own envelope. You really are expected to mail it.
The Good Store has tested this against paper planes, and this is much better at flying into a headwind. It comfortably handles the trip from The Good Store's counter to the door. It can survive a lot of flights and gets better distance with a five cent piece blue-tacked to its nose.
To fly a proper glider (a la Steve McQueen in The Thomas Crown Affair), you'll need to be rich. The Postcard Airplane just needs thoughtful friends.