I remember a long time ago I saw that mission, looked interesting so I tried it out. First thing I noticed is that the mission was called Cesena Fun, or something like that. Didn't spell "Cessna" correctly, and based on many other spelling errors, I guessed English was not the author's native language. There were also several bugs and scripting errors, but it might have been updated too since I tried it out.
I don't mean any offence at the author of this mission or authors of missions like this one. There are many players that love this kind of mission, just like Nogville and some others. But using this mission as an example, I would recommend the use of fewer addons. I tend not to download any mission that uses a large amount of addons, unless it uses addons I already have. Maybe it's just me, but if the addon wasn't good enough for me to use it before, there's little chance I will want to download it just for a single mission.
Because I do not know which version of this mission you have, it's hard to say how outdated it might be. But the version I last used was pretty old, at least a year or two, maybe more. One suggestion is to contact the author and see if there is a more up-to-date version, or ask if he/she can release an update.
Hope this information helped out.