# [05AB1E](https://github.com/Adriandmen/05AB1E/wiki/Commands), 11 [bytes](https://github.com/Adriandmen/05AB1E/wiki/Codepage)

    žMÃDεNÉiu]‡

[Try it online.](https://tio.run/##yy9OTMpM/f//6D7fw80u57b6He7MLI191LDw///EpOSU1LT0jMys7JzcvPyCwqLiktKy8orKKgA)

Or alternatively the `εNÉiu]` could be ``2ι`u.ι``.

[Try it online.](https://tio.run/##yy9OTMpM/f//6D7fw80uRud2JpTqndv5qGHh//@JSckpqWnpGZlZ2Tm5efkFhUXFJaVl5RWVVQA)

**Explanation:**

<!-- language-all: lang-python -->

    žM         # Push the constant "aeiou"
      Ã        # Only keep those letters from the (implicit) input
       D       # Duplicate it
        ε      # Map the vowels in the copy to:
         NÉi   #  If the 0-based index is odd:
            u  #   Uppercase the vowel
        ]      # Close the if-statement and map
         ‡     # Transliterate the lowercase vowels to the alternating cased vowels
               # in the (implicit) input
               # (after which the result is output implicitly)

        2ι     # Uninterleave into two parts
          `    # Pop and push both parts separated to the stack
           u   # Uppercase the second part
            .ι # And interleave the two parts back again (to a list of characters)