If we take a look at JFK's flight schedule for this year's November 6th (which is the winter DST switch date), there are plenty of flights departing between 1am and 2am. For example, a Cathay Pacific flight to Hong Kong at 1:25am.
If one were to actually buy that flight, what would be departure time printed on the ticket? And when would the plane actually depart — on the "first" or "second" 1:25am?
The ticket always indicates the local time at the departure and arrival. So it will indicate whatever is the local time for that flight. Tickets do not indicate the timezone.
Due to the complication with timezones and winter/summer times aviation always uses UTC (sometimes also called zulu time, named due to the letter Z which was designated for GMT) for flight planning purposes.
So, for the purposes of flight planning, the flight is scheduled for 0525Z on November 6; and for the purpose of ticketing, it is scheduled for 0125.
