Do we have a plan for an alien invasion?

yes, use the general population as a human shield

That's not really a question that could be answered here. The reason is because if such a plan exists it's probably classified and not something that would be released to a random person on a Q&A webpage. But chances are, if we were invaded there wouldn't be much we can do about it. The closest galaxy to Earth is over 25,000 light years away from us. The closest star is over four light years away but it's unlikely they have any planets around it. With that in mind, for any invading force to reach the Earth in our lifetime they would have to be able to travel much faster than the speed of light. If they have the technology to do that chances are their military technology is so far ahead of us it would be futile to fight. It would pretty much be like a first grade class with rocks and sticks trying to fight off the whole US Army by themselves.

Honestly, yes there is. The U.S. Gov issued handbooks in the the late 80's or early 90's outlining what steps local government should take in case of a downed ship/first contact.

There sure is Bucko...Tin Foil...yes sirree Bob. I am here to tell you that your soul can be saved OH YEAH Brother. Send me $10,000.00 and I will pray for you non stop until they leave. The added bonus is 2000 lineal feet of 36" wide tin foil. Wrap yourself head to toe my Brother...you know who will take care of your needs and expel those nasty things he created on another planet...you did not know they were also Gods creatures.....you did not go to Sunday School did you my Brother? Better send $20,000.00 I will need to do some serious work to save your soul.

Give me strength, please give me strength!

It wouldn't suprise me. The US has guys in the Pentagon who sit around and make up plans for almost every situation we could run into. They call 'em "contingency plans".

"......alien invasion?"

Already happens hundreds to thousands of times every day.

@AD.. you suck man you don't know dick about ****