I'm sorry NacNak but it is 'metagamey' if one post indicates an ambush and your character suddenly has knowledge of that ambush in the next post.

Geoffrey's post indicated an attack that would hit on-coming players from mid air or the ground, yet in your post you flew [i]over[/i] their ambush. This would make sense if you were trying to distance yourself and observe, but than you just jumped right in front of them, it seems as if you knew that you'd get attacked if you kept flying towards them normally so you went higher to avoid such. Which from your characters perspective, would be metagaming.

As for the whole ordeal, I'm of the traditional stance, GM's RP so GM's word is final. I support his decision in any regard unless I think he is being especially unfair, and in this case, I don't think he is.