So even if it is for $0 I still can not do it? Is this the case?
When USCIS and the SEVIS began the study of the implications of the F-1 visa in aviation and OPT, to supersede the J-1 visa, the US government determined that the "logging of flight time to gain experience" (A rough quote) constituted remuneration/work. I will need to see whether I have this document to provide the actual quote.
Additionally, you do not have to be paid money to be covered by working laws, immigration laws and labour laws, and this is true in many countries not just the USA.