Those are some Military-Related forums on spanish language I use to writte on, english speaker members maybe would find some of these place "weird" because they would not understand anything , but some place have nice pictures or english notes (news, and so)...
Anyway we're not the only place (but the main ;D) you should visit so here's a list:
Forum for discussion of various military themes on spanish. Sections for Spain-related topics, Latin-America related topics, Excellent WWII discussions and various discussions on air-sea and land topics. Sea topics are extremly interesting, mainly thanks a group of guys with awesome radar and naval knowlodgement whose even spanish-to-english translation I recomend. Pay special attention to Eco_tango's post. He's a radar professor at one University there and works with INDRA corporation. Highly recomended.
Forum for discussion of latin-american military issues. Dividided on land-air-sea topics. Very interesting topics on Chilean and Argentinian military topics. Recomended for people interested on latin-american defense issues.
"Military Zone" forums, very well moderated forums, while there is ample sections on air-land-sea topics, air topics are the most actives and the main atractive of the forum in my personal opinion. Very interesting threads, good environment for discussion, and a good defense-news coverage by the moderators and different posters. There are VERY nice Argentinian Air Force and Navy galleries and images, and from time to time, really exclusive material about US aircraft (thanks to personal contacts with some USAF guys) by user Spirit666, plus lots of interesting disucssions on Latin-American (specially Argentinian Defense Issues) and miscelanous topics. Good moderations help you to find a good place for discussion.
The Russian Arms Forum, will close soon sadly is a monotopic discussion/news forum for people interested on Russia Arms topics, is highly recomended forum even for English speakers due to nice news sections (mostly on english) and splendid galleries of pics. Highly recomended!.