What are additional requirements (equipment, licenses, identification, etc.) for a flight operation with a US-based aircraft and crew leaving the US to enter and land in Mexico that are imposed on the operation by the US authorities such as the government or any of its agencies and comprehensive international agencies such as ICAO?
This differentiates from similar questions because I am not asking about the governing set of laws in international territory or what laws of a different country than the home country would apply to the flight; of course ICAO is international in all cases so could be applied as valid in any home country that an aircraft may depart from. Each other, non-US, country's specific laws may vary, so they are removed from the scope of my question.