Shortest duration flight from JFK is South African Airways (SAA) that connects in JNO to Livingstone (Zambia). We did not use a round trip ticket since this tour ends in Cape Town. You can fly back to JFK on several different carriers. SAA will fly you back to JNO to connect for its flight back to JFK and it is still the shortest duration. Delta will connect you through AMS and total trip length will take three hours more.
BTW, We never saw any snakes on our earlier Africa trips. Our guides named an area where there are many snakes to be found, but it was not the southern end of the Okavango Delta.
SAA is reportedly having significant financial difficulty. I would suggest if you book with them, make sure you have good travel insurance that covers potential financial default.
Did anyone fly round trip for this journey from JFK and what airlines did you use.