Thanks for all the advices. And what type of soldier would have the right look for airforce security? Marines? Rangers? I'm a bit lost with the subtleties of US army organization.
Ok pretty much the Air force and Army use the same kit, only different uniforms. But when they are deployed to a combat zone, they will usually use the same uniforms when going outside the wire. If they are going to be doing action in the US, its the Gray Air force tiger strip uniform or Army ACUs. Deployed its DCUs out side the wire for the Air force, or Mult-cam which is what solders in Afghanistan are currently being kited out with. Because ACUs suck, and were chosen so that some office hake in the pentagon could get promoted and or retire and get royalties from the company.
(If you haven't noticed I hate ACUs)
The USMC uses different uniforms(MARPAT), body armor, and still uses the old Kevlar helmets. They also use regular M16a4s were as most of the army and air force have complete changed over to M4s or M4a1s(full auto version)
Also if your just representing some security force augments in the Air force you could be kited out with old fritz style Kevlar helmets, and old school M16s also.
Those are not actually SF(Security Forces not Special Forces) but Airmen and pulled the short straw and have to guard the gate and walk the perimeter. In stead of having the night off. (not high clearance personal)
U.S. army rangers do commando style raids, deep Ops behind the lines, long rang patrols and lots of times get stuck pulling security for Delta Force. You need an airfield taken, or a village wiped out. You call in these guys. They specialize in death blossom, (meaning killing ever thing around them)
But since you said you are trying to go for some UFO stuff I would say go with Air force and SOCOM guys.
Air force because Space Command falls under them and so does Roswell .
So Use Empress mins for SF and paint them up with the Air force gray tiger strip uniforms.
Use Empress Delta force, Eureka SEAL team 6 and USMC Force Recon for just about any group of SOCOM or CIA.(they can use mission pacific load outs and uniforms) So paint them how you want, and call them what you will.
And if you want to do a full on alien invasion or ET has taken over the installation, then snag the conventional USMC from Eureka with all there missiles and other kit, and or Snag a platoon of US infantry from Empress and paint them up in Multi-cam to represent conventional US Army Infantry, National Guard, Rangers, Mech or Airborne Infantry.......ok maybe CAV scouts or MPs but, who wants or needs those losers anyways.
If you ask me things were a lot easier when ever one just used BDUs and DCUs.
then the only differences were in awards and rank insignia, which don't show up at 28mm scale.