First, you need the Vercetti Estate (you get this after killing Diaz). Then, on the roof of the building should be a helipad. If the helicoptor isn't there, then go downstairs, exit your mansion, and do something that gets you ATLEAST one star. If you get two then that's fine but it will be harder to lose the cops. Then, go back into your mansion an go to the helipad again. The Maverick should be there. NOTE: If you get three stars the cops will have a police helicoptor that has a gun or whatever, so be careful. Also, if your helicoptor gets destroyed (and you survive), then go back to the mansion and another helicoptor should be there, most likely another color.