So yesterday I got into an argument because a flier was moving adjacent to my character and he continued his movement with out break away. he did not start adjacent to my character. the pack states Double circle with arrow through it. My move through squares adjacent to or occupied by opposing characters but still needs to break away normally. Is this legal. If he had to stop and roll break away it would have changed the out come of the game.

The flyer would have to stopped if the other fig had plasticity or another way of stopping the move

As Mandark put it, the flier would only need to stop if the figure it moved next to had plasticity or something similar. Most of the time fliers are able to move through other character's spots without needing to stop and only need to break away when they start adjacent (unless they have something that allows them to ignore characters for movements.

Let's break this down. Flight grants you OO> (circles with the line through it) which means :

May move through squares adjacent to or occupied by opposing characters, but still needs to break away normally.

and when do we break away?

Breaking Away
If a character occupying a square adjacent to one or more opposing characters is given an action and attempts to move, that character must successfully break away before it can move,..

Your opponent was correct, unless you had Plasticity or an ability similar to it.

Here is a very solid summary of flight (and just flight... not including any other effect for this)

When you start moving, you have to break away. Once moving you may move past or through opposing characters UNLESS they have Plasticity or a similar effect that cause you to stop (not a new break, you STOP)