Adequate layover times

If you buy the ticket for the entire journey from the airline, they have already figured it out.

If you are contemplating a DIY, multi ticket journey, given the current state of affairs, I would not look at less than 5 hrs

If the pricing and schedule aren't significantly worse, I'd look to try to connect stateside, flying Turkish Airlines from a US gateway.

If choosing between Heathrow and Munich, I'd go with Munich. However, there are others on the forum who've done the transfer-in-Europe bit more times than I have. In terms of time to allow, what I usually do (it wouldn't be adequate right at this moment) is look at the shortest transfer time offered for a transatlantic connection at that airport and add an hour to it. You can do that by looking at the flight options presented to you when you do a search, or you can Google something like "minimum connect time Heathrow" and follow a link. Or you can search for what your planned airline says.

Agree with Scudder, respectfully disagree with Joe0°C.

Turkish Airlines (TK) is the way to go if you can. US cities on the east coast served by TK are: Atlanta, Washington IAD, New York JFK, Newark, Miami and Boston (flights don't always go every day, often every other day). TK is a United partner, so if your home airport has United service, you could do that all on one ticket seamlessly.

I avoid London anytime I can. Munich would be much more manageable (though if something goes sideways, you would have more options going through London). But if it were me, I'd try hard to connect in one of the US cities listed above, and take TK for the long flight. Put yourself on the TK plane for as much of the journey as you can, you will be glad you did.

As many have noticed, more than a few of the major European transit airports (Amsterdam, Frankfort) have been melting down recently unable to handle the glut of passengers, leaving many stranded or badly delayed. This seems like a good time to avoid connecting in Europe if possible.

Thanks for everyone’s input. I will see what we can on Turkish Air from the US.

Frankfurt has similar over crowding problems as Amsterdam?