Flight origination time zone point controls??

I concur that the currently published rule stating date of departure indicates 11:59 p.m. not flight departure time -- but keep in mind which time zone is applicable.

I recently had a ticketing deadline of 11:59 p.m. This particular itinerary originated on the east coast, although I live in the Pacific Time Zone. I happened to call in at 8:50 p.m. PDT and pleasantly said to the agent that I have a reservation that is going to self-destruct in about 3 hours, so I need to get it ticketed. After handling the transaction, the agent (equally pleasantly) advised me that because the flight originated in the Eastern time zone, the reservation would have expired in ten minutes, not three hours.

It appears that flight origination point determines the applicable time zone for ticketing,and presumably, changes.