Cheapest US airport to fly to Europe?

where in Europe?

Use google flights to figure this out - put London as the destination, and look at all flights from the US (pick nonstops), and you will see patterns that will give you the info you seek.

A lot of it depends upon where you live. If you don’t live in the metropolitan areas of NYC, Boston, LA, DC, Chicago or Atlanta, you will have to pay for a connecting flight just to get to those airports. It also depends on how much competition cities have flying to the London airports. If it’s a city with merely one major airline and that’s it, don’t expect inexpensive fares. Don’t travel when it’s high season like June (Wimbledon) either because you’ll really struggle finding inexpensive fares.

No connecting flight is needed from Detroit to London but we are held hostage by Delta. We live near DTW and have relatives or friends drop us off and pick us up. We have no need to park a car and take a shuttle and the McNamara terminal is outstanding. In fact, DTW routinely scores highly in various ratings. We never fly less than premium select and it's never been beyond our budget. I suppose "cheap" isn't our top criteria especially if it involves lengthier travel times, inconveniences and nightmare airports.

We live in South Georgia and prefer flying out of Jacksonville, Florida's airport.
However, I frequently check flights out of Orlando to the same destinations and on a couple of occasions, have saved from $1000 to $1400 flying out of Orlando. When we do this, we always have to book a hotel the night before, because driving time is so long, still, we save a lot.

We generally fly out of the least expensive airport in the Mid South--Nashville. Three budget airlines fly out of there--keeping the airfares down. We can often fly down to Atlanta and on to Europe cheaper than if we drive to Atlanta and fly out. Go figure!

In June, we flew out of our home city of Huntsville, and flights were cheaper than Nashville or Atlanta. The airline wanted us to connect through ORD, but we avoid Chicago like the plague. We flew through Charlotte coming and going, and the connections were perfectly timed. We paid about half what the "normal" airfares were running for Summer.

Finding the cheaper airfares is hit and miss. Sometimes it just takes a little time online to figure out which airports are cheaper on each end of the flights--coming and going. And lowest price is not necessarily the best value. Time in the air is important, and we like to have connections with enough, but not too long, time. Often the cheapest fares will have you on the ground 4-5 hours waiting for the connecting flight--not good.

Statistically (but not consistently) it's JFK.

Very likely LAX (Los Angeles) is one of them due to huge population market and multiple carriers competing on that route. This is similar to NYC.

Two airports that I try to avoid are Chicago O'Hare and JFK. Every time that we have been through those airports, we had problems with delayed flights, terrible security lines with people breaking in line or innumerable gate changes.

There are a lot more US cities than that with nonstop London flights, about 2 dozen

Sure. Charlotte & Philly, for example, have direct service but there is no competition — hence they will not be the cheapest airfares to London.

Lots of variables here, you may think a short question is easily answered.

I think the suggestion about using Google Flights backwards is a good one. Put London as your starting point and put United States as your destination. Be sure to plug in the dates you're thinking of, and other variables like nonstop, class of service, preferred alliance. You'll get a fun little map showing different numbers for different cities.

General rule of thumb, the bigger the city the better.

NYC-London is the busiest route across the Atlantic. There are more flights and airlines than any other city in the USA.

That being said, a connecting flight with Play or Icelandair may turn out to be the cheapest.

AMann, you saw those on Google flights, or somewhere else?

RDU to London Heathrow direct flight.
I took this on outbound to Italy 5 weeks ago.
On return I had a flight from Bologna to Madrid and then direct to Charlotte.
On a trip already booked in May, outbound from RDU to JFk to Psa (Pisa).
Retun FCO(Rome) direct to JFK then a short flight to RDU.
Of course this would not work for those on the west coast.
But enough research and some flexibility there are good itineraries to be found.

As much as I dislike JFK, my husband travels a lot and thinks JFK is much cheaper than ATL. NY and Boston both have daytime flights(compared to most flights which are overnight), and the one time we did this, it was wonderful.

Two airports flying non-stop to London LHR and Gatwick are SFO and Oakland. I 've done both, but given the two I much prefer OAK. The flights go to Gatwick which is more convenient for me in terms of public transport than landing at LHR.

"can’t get Google flights or Kayak to do this, accept US as a destination."

I just did this and it worked fine, spell out United States. You can also use North America to see more flights.

I live in Philly but have found Newark (EWR) or JFK to consistently be pretty cheap to fly from. Boston and BWI also have pretty cheap fares. I sometimes take the train to EWR or BWI just to save $200+ on a ticket. But I pretty consistently see tickets from these destinations to London for under $500