My Rheem unit tripped off yesterday. I took of the panel and noticed a block of ice on the coils and on the cooling transfer plates.

Do I just let the ice melt and check air flow? Or what else should I do, going to be in the 90's today.

You really can't do anything until the ice melts... but the first thing to do after it does is check airflow as you thought.

Or Freon levels.