The biggest challenges we had were more political. Getting buy-in across the airline as well as _support_ from the airline side to integrate their data and system into ours.
Sadly, it was a people problem, not a tech or algo problem.
So, did you manage to "tackle" the people problem in the end? How did you get them to move and integrate with your system in the end? Was it a bottom up (from the end users) or top down (making it part if company strategy) approach?
Sadly, I don't have these answers. I ended up quitting to go on a long sabbatical.
Last I heard, the airline scrapped the entire project to continue doing things the old way because they felt it was too much work on their end. ¯\_(ツ)_/¯
Sadly, it was a people problem, not a tech or algo problem.