Bullet blimp.

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This ingenious swivel gear pearl is the "Gimmick" pictured below. Inserting a craft stick between slits in the sides of a plastic bottle would anchor the propeller inside the rim to produce a ducted thrust vortex. The pearl allows the rubber band to counter rotate the cycloidal wing while allowing the bearing to spin the propeller too. A thin dowel can hold the rubber band to the back.

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Sodhart glues the soda straw to the top of the soda can. It glues to the craft stick the same way. The pearl acts as a friction gear set between two short lengths of plastic soda straw! This is a master stroke of gimmickery! The pearl ball is actually standing still while both sides are rotating in opposition. A quick and dirty Barrel Gear! The problem with the Pepsi can is that the spiraling fins are catching a reverse back wash from the propeller. Minimized drag and Máximum  vortex thrust achieved when channeled through the center!

This is a "Cyclo Gyro" not a helicopter. We can fashion a couple of cool spiral fins cut from a second bottle. This experimental design will fly ten times better with the propeller inside the rim of the cycloidal gyro wing.

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Propellers inside the ring:

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I wrote Siddheath Creations on YouTube and suggested positioning the propeller inside the cone, and he replied and said he will try it! So let's wait for the next upgraded version!

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Ducted 3 blade fan is ideal!