I am sure this has been asked and answered 1000x so my apologies for the question. I am flying on 9/1 LAX-JFK-LHR and then transiting on to Croatia that same morning. As I understand it, transiting passengers do not need any type of tests to fly into LHR, correct? Of course we will not be leaving the airport but maybe have to switch terminals.
I do know that upon my return to the US, I will need a Covid test (not sure what kind) which I will take care of in Dubrovnik.
thanks--very informative forum during a confusing time!