Immigrationboards.com

I am an American citizen who had lived in the UK for four years on a Tier 2 visa, which ended in the summer. This July, I married my wife, a Dutch national who also lives and works in the UK.

We applied for a residency card in August, and received a letter of application in September, allowing me to work (I subsequently began employment in November). We also requested the return of our passports. I received mine in mid-November.

We are planning on flying to the United States for Christmas. While there, should I apply for a family permit? Does anyone know what the process entails? Should I list my address as the US or UK? I plan on returning 10 Jan, with my wife following a few days later.

from my personal experience you don't need to apply for anything else, the residence card should be enough to get you through immigration. In your case the HO letter, marriage certificate and a little chat at immigration should be fine (someone who had a residence card / married to EEA national)

Just to be clear, I do have not yet been issued a residency card. I merely have a Certificate of Application.

It should be fine as they will see that you've applied. It might take a little longer than usual doing the talk etc but ultimately should be fine, especially because you arrive with your wife.
They will probably stamp you with a normal visitors visa for the time being.

I have a residence card on my passport that expired this summer however I had a few last minute/emergency trips and upon returning to the UK all I had to do was explain that I would apply for PR as soon as possible.

I am not sure if this is the "official within the law" way but that was my experience this summer. I find that most of the immigration staff at the airports are very helpful and reasonable.

Maybe one of the moderators can shine a light here in this thread.

My wife will not be traveling with me. As stated in the original post, she will be arriving a few days later.

oops, sorry mate, I misread that bit.
Again, speaking from my experience only. Arriving without your wife is also fine as long as you have the documentation to prove that you are married to an EEA, applied for Residence etc.

I guess that in their eyes they can tell you are not trying to circumvent the law, just went back home for Xmas and you are indeed settled in here.

It might take a little longer at immigration, but it should not be a problem to get back in. And probably it is not a good idea to have two application going around at the same time at HO