watch out!
sorry, you can not log 1500h in comair unless you have a work visa.
J1 visa is only valid for a 2 years period, during these 2 years, you can only work for 6 months in the same field . something that Comair will not tell you .
Ask your US embassy if you have any question regarding this matter.
Comair will tell you anything as long you pay them.
even under a JAA program, you need a US work permit(green card).