Stealing object? What?
Just use the platform behaviour and apply a -y vector to it when you want to flap. Then check it's y position when you want it to glide and ensure it never goes below this level. You can top this off by lowering gravity, so it falls slower, and give it a constant X movement.
Alternatively, you can use the custom movement.
This question is easy and suggests you haven't really tried it out. There's a manual and even a beginner how-to section to avoid pushing the more advanced users questions down.