FlyingForFun,
If you are flying as PUT under a student medical, you must be on either an M-1, J-1, or F-1 Visa. The reason is because he is not legal to fly in the U.S. without the signoff of the instructor. Note it is a Student Medical and as a Student you need either an M-1, J-1, or F-1 Visa.
Happy flying,
Capt. Richard J. Gentil, Pres.
Naples Air Center, Inc.