The question is would the general public use an indoor viewing area if there was one? The last time I was in the old spectator gallery there was hardly anybody in there; and that was at the height of summer. I know that the pier developments blocked a lot of the views and it wasn’t ideal from a spotters perspective, but for everyday joe public it still offered a decent view of the planes landing and taking off.
I think PK was probably right in what he said as you would often see spotters in there with their own flasks and sandwiches which is fair enough; but that’s not going to make any profit and sadly in today’s economic climate that is what it’s all about.
Besides, there isn't anywhere suitable for an indoor viewing area anyway so the best one could hope for would be something along the lines of the viewing park at Manchester.