What should the next lette be? A Z E B I Y O

The letter C, because the pattern is this (I think):

Every two letters it states the vowels (a, e, i, o, u)

Then in between every two letters there starts a pattern of, saying the alphabet in order and saying the alphabet backwards.

In other words they merged these two lines:

A, B, C, D, E ...

+

Z, Y, X, W, V ...

=

A, Z, B, Y, C, X ... etc.

then by adding this pattern of vowels you get:

A, Z, E, B, I, Y, O, (C), (U), (X) ...