Some basic flash samples of mine...
Most of these were created in Flash© CS4. Although I am still a supporter of Flash© and most if not all Adobe© products, I have switched focus to HTML5/CSS3 transitions for banners and marketing ads.
Flash vs HTML5/CSS3
It can really depend on your target audience. Many Tablet and Mobile phones do support SWF files so users will be able to view the content. Even iOS which does not natively support SWF files does have browsers in the app store that support Flash content up to certain versions.
Redirect and User Agents
The best plan is to provide duplicate content that can be seen by a variety of users. Typically a few scripts embedded in the master HTML template will direct users to specific pages that contain media and code specifically designed for that platform. This site for example uses a simple JS script to read the primary user agent data of the browser that is viewing the content and direct from there. So for example, when a user goes to my site on their iOS or Android OS device, they are redirected to THE MOBILE PAGE automatically when the main landing page loads.