Coast Guard Authorization Act of 2019 This bill reauthorizes the U.S. Coast Guard and the Federal Maritime Commission for FY2020-FY2021 and authorizes a specified end-of-year strength for active duty personnel and military training student loads for the Coast Guard for such fiscal years. Among other things, the bill addresses (1) retirement grades for Coast Guard personnel, (2) promotion authority for Coast Guard personnel, (3) the use of unmanned maritime and aircraft systems in the Coast Guard, and (4) access to child care for Coast Guard families. The bill revises or sets forth policies relating to the Coast Guard, including vessel safety standards, vessel operation requirements, acquisition workforce authorities, due process protections under Coast Guard Academy policy on sexual harassment and sexual violence, continuation of pay during a lapse in appropriations, Coast Guard advisory committees, reporting requirements, the use of engine cut-off switches on recreational vessels, and polar security cutter acquisitions.