Is there anything I should be aware of that will cause issues?
If your outbound flight to JFK is cancelled or late enough that you end up missing the flight, you will need to pay a new ticket yourself as Delta has only the responsabilityresponsibility to carry you to JFK, not LON (some insurances may also cover it), for 5 hours it's unlikely but be mindful of that and of the timing too, to not miss it yourself.
Delta and Virgin Atlantic serve both Terminal 4 (I'd suggest you check your specific flight, if your flight lands in T2, you will need to pass through TSA again once arriving in T4 and again procedures will depend on the following)
Once you arrive in JFK, the procedure essentialyessentially boils down to if you can check-in online for your flight to London and what you want to do
If you can check online and both flights are in the same terminal, you can just stay in the gate area for your next flight and wait
If you can't, just exit the secure area, chill out and wait for the check-in to open and pass through TSA again
If you have checked in online, but want to leave the secure area, you can just exit while making sure you pass TSA early enough not to miss your flight
If you are at a different terminal, the above applies, except that you will exit the secure area to transfer
To make your connection, follow signs for AirTrain. You will need to reclear TSA security once you arrive in your departure terminal.
From the Port Authority
