Originally Posted by
Often1
OP - Without knowing your citizenship & residency, it is impossible to answer. You list MSY as your location, leading me to believe that you are at least a US resident if not citizen.
Yes, an appropriate Covid test obtained pre-departure in the US could be used both for entry to Germany and then to board and return to the US.
As with all international travel, have you run your details through TIMATIC?
Not only do you need to run it through TIMATIC you also have to assume the ticket agents have common sense. I did 26 same day return from LAX-NRT Aug-Dec 2020 and was denied boarding 6 times because the ticket agents at LAX couldn't read. It clearly read as ok to do but some agents were dead set that I have to clear customs and immigration when I land at NRT which is never the case for transiting passengers. United in Narita and supervisors in Chicago all confirmed I was allowed to do this but some agents wouldn't budge and wouldn't print my boarding pass.