A useful technique in any animation is to use "Loops". Loops are basically animated sequences that repeat themselves over and over again, but look as if they are one continuous flowing animation.
For example, you may have seen an animation where clouds are going by in the background. Although they appear at first glance to be different clouds, they are in fact the same clouds, but the frames are just repeated.
1. This is a tutorial on animation (not drawing), so before you begin, you will need to know how to create (3) three graphic symbols for an airplane, a big cloud, and a little cloud.
2. Also, be sure to go to the Properties inspector and change the background color of the stage to a light blue to represent the sky.
3. Get your images for the plane and clouds, make sure they are "Graphic Symbols" and that they are available from your Library.
(As you can see below, the images were imported as Bitmap graphics to the library, they were later converted to Graphic Symbols)
4. Next create three layers and name each layer "Cloud 1", "Cloud 2", and "Airplane". Make sure that the "Airplane" layer is inbetween the "Cloud 1" and "Cloud 2" layers.
5. Create a new "Movie Symbol" in Flash by clicking F8 or going to Insert -> New Symbol in the top menu.
6. The "Create New Symbol" box appears. Enter the name "Big Cloud", and click the "Movie clip" option. Click OK to create the "Big Cloud" movie.
7. Open the "Big Cloud" movie and drag your first cloud into the first frame of the only layer of the movie. Make sure to position the cloud on the very left of the screen.
8. In the timeline, create a keyframe on frame 20. On this keyframe, move the cloud to the other side of the screen.
9. Add a Motion Tween to the frames in between.
10. You should now have a movie of the cloud moving from the very left of the screen to the very right.
11. Now, repeat steps 4 through 9, except for Cloud2 and name the movie symbol "Little Cloud".
12. Once you have the two cloud movies completed, you are ready to add all the elements to the main stage in your scene.
13. First click to select the Airplane layer and drag the Airplane graphic symbol from the library. Place it somewhere in the middle of the stage.
14. Next select the "Cloud 1" layer and drag the "Big Cloud" movie symbol on to the stage. Be sure to place it so that the cloud is off to the left edge of the stage.
15. Then select the "Cloud 2" layer and drag the "Little Cloud" movie symbol on to the stage. Same thing, make sure it is off to the left edge, but place it somewhere lower or higher than the other cloud.
16. You're done. Test the movie and watch the clouds loop over and over.