If you or your designer uses Flash Professional as a paint tool, optimize the shapes under Modify→Shape→Optimize. Then, convert strokes to fill.
Use a utility to optimize PNG and JPEG formats. Both PNG Optimizer (http://www .pngoptimizer.com/) and ImageOptim (http://imageoptim.pornel.net/) are free and will reduce the file size of your images.
If you have several vectors that are not moving, are grouped, or are on top of each other, convert them to a single bitmap. Crop the alpha channel of your bitmap carefully. Remove the alpha channel completely on PNGs if you don’t need it. In Photoshop, use the File→Save for Web & Devices option instead of File→Save As. Save your image as PNG-8.
To monitor the rendering process, make the redraw regions visible. They are the dirty regions that are processed and rendered. In AIR, you do not have access to the context menu, but you can show the regions in code and choose the color: