Does anyone know some good masking tips for painting foamies. I've heard sticky plastic wrap and sticky note pads work can anyone verify this?

A good primer!

What kind of primer would you suggest? I'll be using rustoleum spray paint because that wont melt the foam.

It also won't stay on very well, especially if it's a belly lander. I assume your plane is EPO? I painted a Stryker a few years ago with Rustoleum. The top did ok. The wingtips lasted about a day. I put packing tape on the bottom in the wear areas, and that's now pretty much the only place it still has paint.

yes it is the durable epo foam. it is not a belly lander it is a tail dragger gear setup. Would it help if i used a polyurethane after aswell as a primer?

I doubt it. The problem is that the foam is too slick at the microscopic level for the paint to really stick to it. Krylon Fusion is meant to fix this problem, but I haven't ever tried using it on EPO. I would definitely do a test piece first.

Thanks for the tip! I will definitely use a test piece and keep you updated. since this is a prepainted model should I worry about removing the paint that is on there already, and if so what should I use to remove it?

Here are the photos of my first test on home depot insulation/craft board. You can see on the lower part the krylon fusion melted the foam, but on the upper part where is used a poly primer it did not melt the foam. When I tested to see the durability when masking with normal masking tape it pulled off a few flecks. when using note pads for masking they did a much better job at not pulling off any flecks and I found had a better seal (the paint never bled through or under) than the masking tape. I still have another test on epo foam to do.

The testing on the epo foam (at least i think its epo, its the only scrap piece i have) did not go so well. It still melted the foam after 5 coats of spray on water based poly though not as bad as without the poly. When masking with the normal painters tape it pulled most of the paint off, the notepad again pulled no paint off while giving a mostly clean line. I think it would have been a cleaner line if you sprayed away from the painting line. I'm gonna try to find something that I know is epo foam and see what it does after six coats of poly

You'll probably have a compatibility problem with the poly. The question arises as to whether or not the poly you are using is impervious to the solvents in your paint. If so, how long does it need to cure? There is also the question on whether or not your spray paint can mechanically adhere to the poly. If it's glossy, it probably can't. Then there is the matter of weight; foamies are usually light planes, so 6 coats of poly is a significant addition. I think you'll need to find a single coat solution to make this work.
Rustoleum isn't that bad. It's not hard to touch up when it does get scuffed.

Weight-wise the poly really doesn't make that big a difference after six coats of poly all around on a homemade airboat it maybe added a ounce or two at most. I used a rustoleum clear enamel spray and that melted the foam but i have been having a hard time finding any other kind of rustolelum that's not an enamel. Was it just the foam i was using or are there other non enamel sprays and I just have to look harder?

Rustoleum makes a lacquer too, but that will probably be more aggressive with the foam. Your plane may not be EPO after all. White styrofoam (expanded polystyrene) will melt with most any spray paint.
If that's the case, you'll probably do better to paint it with something water based and call it good. Household latex might work.