Kinda Frustrated its 1:30am and here is the finished product.

I got to make a retirement cake for the practice for a co-worker of my MIL.

the air bubbles left holes, even after trying to smooth over with hot water on spatula...

any reason why?

I've had this problem on bigger cakes too. I've got some ideas, but don't know if they're the answer.

What size spatula are you using? A larger one is really needed. Also, I've found that I need to put a lot of icing on to start the spread and then go for it! No stopping up short or trying to take baby steps with the spreading. When I use enough icing and spread with a confident sweep, I don't have the bubble problem. The smaller cakes seem to be more forgiving of the spreading technique used.

Another problem could be if you're not using the icing right away. I always rebeat mine if it's been out a while

Hope this helps.

Sarah