JFK layover time

Delta uses Terminal 4 for all their flights. When you fly FROM the US TO Europe with a layover at JFK, all you need to do is walk from one gate in Terminal 4 to another - no need to go through security. (This is assuming you are traveling all on one ticket, not two separate tickets where you would have to exit security, retrieve luggage and check in again.) So, unless your first flight is really, really late, you should have plenty of time to catch the second flight with 1-1/2-2 hours.

Your previous experience was flying back into the US. In that case you need more time because you have to go through passport control and customs, as well as security.

If your flights are all on Delta carriers (not to be confused with Delta partners) then you will arrive and depart through terminal 4. There will be no need to exit that terminal for any reason. Luggage will be checked through to your final destination as well. If for any reason you exit the terminal then you will have to clear security to re-enter airside for that terminal and for any other terminal. Some of Delta’s partners (i.e. Virgin Atlantic) use terminal 4 but some use other terminals (i.e. Air France).

If you arrive on a non Delta carrier and have to connect to Delta then the trek begins. Depending on the airline or partner you may or may not have to change terminals. I recommend avoiding flight itineraries that require a change of terminals at JFK. It’s easy to do but time consuming.

If heading to London then that should be enough time. If you were returning then you would need to plan time for passport control and customs before heading to your flight for Buffalo.

Thank you for the replies, they're very helpful.

I hadn't thought about the difference between outbound and return procedures. This will make my planning much easier.

My worry GOING with these types of flights is what happens if you miss the connection at JFK? How long until they can get you on another flight?

Nice thing about JFK to London is Delta has a lot of flights. I had a plane go out of service when I was flying to London last year. I was only delayed by an hour after they canceled the entire flight.

I flew through JFK on the way to Rome in May. My flight from Minneapolis to JFK was late because we sat on the tarmac waiting & waiting (over an hour) for our gate to be cleared. They finally took us to another gate. I ran to my connection flight and made it. That plane loaded sat at the gate for a long time before we took off. So my advice would be to select a connection with a lot of buffer time.

Detroit makes for an easier entry to the US and connection than JFK, so keep that in mind for the return.

Thanks for the tip, I'll look for that.

My worry GOING with these types of flights is what happens if you miss the connection at JFK? How long until they can get you on another flight?

Yes, that's my biggest concern.

Nice thing about JFK to London is Delta has a lot of flights. I had a plane go out of service when I was flying to London last year. I was only delayed by an hour after they canceled the entire flight.

Probably wise to book an early flight so there will be those options just in case.

I flew through JFK on the way to Rome in May. My flight from Minneapolis to JFK was late because we sat on the tarmac waiting & waiting (over an hour) for our gate to be cleared. They finally took us to another gate. I ran to my connection flight and made it. That plane loaded sat at the gate for a long time before we took off. So my advice would be to select a connection with a lot of buffer time.

True, though it's a trade-off between a shorter layover with 10 hrs total travel, or a longer layover with 12-14 hrs total.

Thanks everyone.