I was offered the same, however some people commented me it was illegal, so I've asked SEVIS and the answer is quite straight forward:
Sent: Monday, March 28, 2016 4:04 PM
To: SEVP
Subject: VISA F1 for Flight Instructor Courses
Hello!
I've been offered an opportunity to proceed with my CFI (I and II) and CFI ME courses and after complition stay some time for OPT with an F1 visa given by a flight school on Florida, however I've also receive some feed back from other sources that this is not legal if you do not complete also basic training (PPL,CPL, IFR) wich I already done in the past in USA with my F1 VISA, can you confirm if I can proceed?
Best regards.
Answer:
Good afternoon.
Thank you for your inquiry. If you would like to attend a flight school, you will need to file an I-539 to change your visa status to M-1 with USCIS.
An F-1 student cannot attend a flight school.
If you have additional questions or concerns, please contact the SEVP Response Center
Kind regards,
SEVP Response Center
Student and Exchange Visitor Program
US Immigration and Customs Enforcement
500 12th St. SW STOP 5600
Washington DC 20536-5600
Phone:
703-603-3400
Toll-Free:
800-892-4829