Set your stage to scale (but you know that will reduce performance and clarity of the bitmaps), nonetheless let you view it on a screen smaller than your target. If it's just a FLA project, on your first frame in an empty frame set the StageScaleMode and StageAlign:
stage.scaleMode = StageScaleMode.NO_BORDER;
stage.align = StageAlign.TOP_LEFT;
Sometimes I work on AIR kiosks on my laptop just to troubleshoot and it's not a HD screen so I need to scale it down to see the whole thing. NO_BORDER will scale but maintain aspect ratio. When you're done just remove those lines of code.