It depends on the part somewhat, but I typically use superglue or a quick drying 5 minute 2 part epoxy. For a large mount on a flat area, like the cockpit of a Valkyrie to the hull superstructure, I'd use the epoxy and a bit of the superglue to hold it in place. For the wings to the body, I'd use superglue.
Now, that being said, you typically will get a nasty looking gap at any joint. I use Apoxie Sculpt to hide those gaps. GW has been touting this stuff for some of it's modelling and sculpting for the last few years. It really works pretty slick. I like it because you can actually smooth it out with a large wet brush (about a tank brush sized). You can really feather out the paste in this fashion. Once it dries, you can go back and get a second layer if necessary. I haven't done any pods yet, but I'd think it will work well there too.
http://apoxie.sculptingstudio.com/