What planes are giving you the trouble? All planes must have these folders-model, panel, sound, texture; and thesel files-.air, .dp. cfg there? Also all folders contain appropriate files?

Try this Links

I have decide to make a post placing most of the links I have with CFS2 planes. I hope to you like this post. My only objective is to help fellow members to find most of the planes that have been develope  throughout  the years for this community by its dedicated developers. 
 
My first recomdation if you to install Acman from this Website that will anable you to install most if not all this planes in different Hangars and in different CFS2 Installs. 
 
1.http://fly.to/mwgfx# ;
 
                      A WORD OF CAUTION 
 
When you use the Acman and create a new Hangar you need to include the stock planes. What you can do is to make a New Folder and place a copy of the Stock planes in it. When you make the new Hangar just copy  the stock planes from this Folder. Remember also that you are limit to 95 to 100 planes per Hangar. You do get up to18 Hangar with this program. 
 
 
My secound recommendation is for you to install this utility from Sim-outhouse that will allow you to change planes and ships with in a Miision and Campaigns in secounds.   
 
It also will give the ability to change whole planes Hangars and convert them into Ai Bandits in Quick mission. 
 
This way you do not have activate plane after planes manualy. Its call mk_cfs2_uti2v.zip 
 
2.http://www.sim-outhouse.com/index.php?loc=downloads&page=downloads&FileT ype=cfs2-utilities 
 
Now let start the best of planes and Skin plus panels available for this Sim. 
 
1.Simviation planes.What great collection:http://www.simviation.com/cfs2aircraft1.htm ;
 
2.Sim-outhhouse hundreds of planes. One of favorite Website:http://www.sim-outhouse.com/index.php?loc=downloads&page=downloads&FileT ype=cfs2-aircraft 
 
3. Simhouse Skins:http://www.sim-outhouse.com/index.php?loc=downloads&page=downloads&FileT ype=cfs2-skins 
 
4.Sim-Outhouse outlet planes:http://www.sim-outhouse.com/master_ftp/cfs2/cfs2-aircraft/ ;
 
5.Sims Outel Skins:http://www.sim-outhouse.com/master_ftp/cfs2/cfs2-skins/ ;
 
6.Wai planes. It those only have nice planes but one of the P51 avalable in the Sim World:http://acwai.00freehost.com/index.html ;
 
7. Netwings planes. One of the great collections of planes ever:http://www.netwings.org/library/CFS2%5FPlanes/ ;
 
6.Netwings Skins. Very nice ones indeed:http://www.netwings.org/library/CFS2%5FSkins/ ;
 
7.World war one planes available right here:http://www.aer.ip3.co.uk/cfs2_9.htm ;
 
8. A nice Web for planes:http://myzone59.ath.cx/combatflightsimulator/avions.htm ;
 
9.Avsim a nice all around Website for planes and o 
ther things:http://www.avsim.com/ ;
 
10.http://www.big.or.jp/~chah_s/beyond1945/htm-e/6/index.html ;
 
11.Nice Mosquito:http://bescaravage.free.fr/bruno/pages/entrez.htm ;
 
11. World war one and P26 planes:http://www.mwsteckel.com/CFS2.html ;
 
12. Absuad self auto install upgraded planes available Here:http://www.absquad.net/CFS2_ABSquad.htm ;
13Nice   
 
He177 :http://www.geocities.com/kg200hangar/cfs2aircraft.html ;
   
14.French Web with lots of planes. You will figure it out:http://cfsfrance.altajeux.com/ ;
 
15.DAG has Russian planes:http://cfsfrance.altajeux.com/DAG/links.htm ;
 
16.French Fighter D520 Dewoitine:http://perso.wanadoo.fr/jm.mermaz/telecharg/d520gmax/d520gmax.htm ;
 
17.Website dedicated to the P51:http://www.btinternet.com/~duxford.legends/pages/P51.html ;
 
18.Missions and Bf109:http://www.angelfire.com/ab5/cfs2brits/Downloads ;
 
19.Easy Kill has nice Skins and effects:http://storage2.free.fr/ ;
 
20.Easy Kills planes are here:http://storage2.free.fr/ ;
 
21.Spanish Web with some more planes: http://usuarios.lycos.es/flakiten/ ;
 
23.This site has many nice Me110 and some other European planes:http://www.groundcrewdesign.com/cfs2planes.htm ;
 
24. Av planes:http://www.netwings.org/library/Avhistory%5FCFS2%5FAircraft/ ;
 
25.This Web also CFS2 planes:http://www.surclaro.com/downloads_c2_240_hitsA.html ;
 
26. Best site for Italian planes:http://www.isoliti4gatti.com/warbirds.htm ;
 
27.Good site for Ju52:http://www.ju52-3m.ch/models.htm ;
 
28.Best site for Ki44:http://pigeonh.free.fr/ki442.htm ;
 
29.One of the best Websites for Japanese planes and some German planes as well. I love the Ki43 and Ki84:http://translate.google.com/translate?hl=en&sl=ja&u=http://hago003.hp.in foseek.co.jp/&prev=/search%3F3Dhttp://hago003.hp.infoseek.co.jp/index.html%2B%26hl%3Den%26lr%3D%26sa%3DGhtt...;
 
30. Here is another Website:http://home.iprimus.com.au/mandcsilver/ ;
 
31.Here is another Japanes Website with some nice Japanese planes:http://yashico.cool.ne.jp/ ;
 
32. Here is a Website with rare British planes:http://www.pavaservices.com/cfs/ ;
 
33.http://uk.geocities.com/wily_crocodiley/cfs2/aircraft.html ;
 
34.Another British Website with guess what? More British planes. I love their Spitfire and Hurricain. It also has a nice Ki43 with all around view from the cockpit: http://www.raf662.com/modules.php?name=Downloads ;
 
35.Modern planes:http://www.anglovirtual.4t.com/photo.html ;
 
36.Bruno planes:http://www.br-planes.fr.st/ ;
 
37.Green Stuart Web includes World war one and two planes. It also includes the only G4MI Betty in this Sim:http://www.domicilium.com/peveril/hangar/hangar.htm ;
 
 
 
 
 
James007

Again, what aircraft is it your're having problems with?
Each individual aircraft folder has to have the following sub-folders: Model, Panel, Sound. The model folder should contain the .mdl and .cfg files. The panel folder contains the panel.cfg file(s) and possibly .bmp file(s). The panel folder will be empty for AI aircraft. The sound folder contains the sound.cfg file and may contain .wav files. The aircraft folder should also contain the aircraft.cfg, .air, and .dp files.
If all of those are there and it still doesn't show then it may have been modeled using an older program.