Hello again ponyboy314, we seem to be going all over the place with this and not getting far, such is modding for you, I agree with Alfie that downloading B.A.T might be your best bet as it is the most up to date mod pack at the moment.
Anyway, back to your question about about your air.ini., yes, that is what is known as 'comment out' it stops the game reading that particular line, using that and adding the minus to a folder means it will be missed in the games search when loading from the mod folder, things in the mod folder are loaded before those already in the game class files.
I assume the other aircraft listed are your additions to what was already in your install, D.B.W or whatever, are they all working?
This will seem a odd question but have you checked the aircraft you are adding are not already in your mod pack?
Even though D.B.W is quite old now it is possible there is some individual still adding patches even for new released stuff, I do not know because I dumped mine long ago, however, what you do not want to do is add something in that is already there because normally things added to mod packs are the most up to date with all necessary fixes made of reported bugs, adding a older version will break things.
Sometimes, there are many instances where the link in the first post of any thread is not necessarily the most up to date. Fixes are added by various folks in the thread but not always added to the first page to replace the original link which is why I advise checking through the thread and also making sure your mod pack does not already have them.
The Helldiver is from the FreeIL_2Modding site and they are best to help you with it, I will say again that the best thing you can do is go to that thread and read through it carefully, there are a few pages but it might be someone already experienced the issue you have with that particular aircraft and added a fix, those fixes might have been added to a updated link in the first post of the thread, however, they might not. I think the Helldiver is from Barnsey, he is usually very thorough but always check everything.
That particular aircraft has a number of variants like the Piper, it is a set, they all work for me in 4.12, however, I think they were made for 4.12 but I might be wrong so they might not work in 4.10, you need to be sure that the set is for the game version you add it to and does not require any dependency such as cockpit, FM or weapons pack to make it function. Can they be used individually or do you have to install them all? Check! Sometimes there might be a link that points to a earlier mod you also need to install to help them function, you have to do the legwork on this, none of us will do it for you, check, check and check again.
Sorry to keep repeating these things but to save yourself trouble you need to develop this mentality.
Many mods over the years have been released without being finished, we are not all masters of modding, each of us can do somethings better than others, however, some we just cannot do and so release things to the community in the hope they can join the dots and make things work.
I have B.A.T myself but usually do not add anything to it, not that I cannot, just that I know when it is patched any issues with things added in are sorted, no headache that way.
My main install is just for modding or just seeing what happens with new stuff, I play in B.A.T.
A bit more useless information for you just to overload your already messed up head, seaplanes, if you move a floater made with 4.10 classfiles into a later version such as 4.12 it will not use the water based airfields it should. If you put a floater made using 4.12 classfiles into a 4.10 install it will crash it. For some strange reason T.D, those still officially updating IL-2 for 1C changed the name in the class from Sailplane to Seaplane, or the other way around, I forget.
Yeah, why? Who knows but this is what you have to contend with, get a modpack and leave things as they are.
Apologies for prattling on again, writing this while having my morning cuppa.
Or was, it is nearly dinner time now, health issues mean it takes me a while to write, thinking takes even longer.
Take care and be safe.
Wishing you all the very best, Pete.