Our schedules data is sourced from around 900 airlines that send SSIMs to Cirium. We receive schedule updates every day and then compile the data into a master file that gets updated Friday night. There is a process in place for airlines that do not publish their schedule the full 11 months forward. I’ve highlighting the process below.
We do extend schedules for airlines with a schedule filing less than 11 months forward,
unless they explicitly request us not to, or if we know that they have ceased operating
G4 is one example of the few carriers that have asked us not to extend their schedules past
their end date. Conversely, F9 is one of those airlines that we DO extend if the end date
doesn’t extend forward 11 months.
For the most part, airlines don’t really focus on their schedules outside 6 months – they are
basically extensions of the closer-in schedules with known seasonal adjustments. Sometime
between 4-6 months, they figure out their levels of service. Once inside 4 months, they’ll
lock down equipment type, and the time of day. Inside 2 months, most of the change is
due to operational issues (crew, maintenance, facilities). Once the schedule has the crew
assigned (about a month out for the start of the crew month), something major has to cause
a change – e.g., environmental issue (hurricane, SARS, volcano, etc.).