U.S. carriers generally allow one to fly standby on an earlier flight
than booked (on the same day) if there are open seats, for no
additional charge. The one time I asked about this when traveling on
a flight within Europe the agent politely but firmly said that I could
fly only on the exact flight that I had booked. This was on BA,
flying out of CPH.

Is it general policy within Europe not to allow same-day standbys, or
does it vary from airline to airline or country to country?

Before anyone flames, I'm not arguing one way or the other, just
scoping out the possibilities.


--
"Flight Now Leaving Reality, Please Fasten Your Braincells"