Gathering data of airport/airline flight schedules/timetables

I need data (arrive/departure times and so on) of airport/airline future flight schedules/timetables.

It must be free (I'm not willing to pay for any APIs) and I'm looking for full data for whole year not just specific day which most APIs provide.

I looked at related questions and tried googling but to me it really seems like there still aren't any solutions. Especially as I'm interested in original raw data sources. Does anyone know where they would be available?

Currently it looks like my best option is to just directly parse from airline pages, for example Turkish Airlines have PDF file which could be parsed. But it's more complicated for Etihad Airways as I didn't find such list only this interface but there I would have to query every source/destination for every day which is huge request count.

Also does anyone know open source libraries/applications/databases which already do this or something similar? Does anyone have experience working with flight data? And really even in 2016 there still aren't any open public access to direct data from airlines?