Question: I'm a female solo traveler (US passport) who would like to join in with few tourists arranged by www.uppersia.com in Iran. and who would like to find out if there's a direct flight from NY JFK to Tehran?

Answer: No, there is no direct flight from NY to THR. The easiest would be through Dubai with Emirates. But for more information you can check http://www.uppersia.com/Iran-transport-services/iran-flight-ticket-booking-service.html

Check the cheapest Iran tours at http://www.uppersia.com/Iran-tours