Which episode do the captains and luetenants learn to walk in mid-air?

You are likely thinking of the episode "The Day the Earth Stood Still" from the animated series "The Transformers" (1984). In this episode, the Autobots and Decepticons are forced to walk on a "Force Field" generated by the Dinobots, who believe it's a better way to move around.

However, the "captains and lieutenants" you are referring to are not actual military ranks in the Transformers universe. The Autobots and Decepticons are led by Optimus Prime and Megatron, respectively, and have different ranks within their respective groups.

If you are referring to a different episode or show, please provide more details and I will be happy to help you find the specific episode you are looking for!