When to Add 了 in the 太....了 Structure The grammar structure for expressing too much is 太.....了according to my grammar book.
And to express anymore...

Eg. I don't like you anymore.
       I don't live there anymore.

...You also use 了 at the end.

So how are you able to differentiate between whether 'too much' is being stated or 'not anymore' is being stated?

Example sentence:
所以，现在已经不太爱坐飞机了。
So, now I don't like taking planes anymore.
If there was no 已经 how would I know that the person is saying 'not anymore' or 'I really don't like taking planes.'

I've seen that sometimes there is no 了 when expressing too much so when do I add it when do I not? 

Does the 已经 clarify which one is being said since it's used for being expressed with 了 when saying 'not anymore' (though my grammar book says only to use 已经 for emphasis)? If so, do I have to add it every time to avoid confusion?
Continuing your example:
if we remove '已经'  


  所以，现在我不太爱坐飞机了


still means 'not anymore' because of '现在'. The reason you say '现在' in this sentence must be to compare past and current, so '已经' is optional in this sentence.  

Now if we also remove '现在'


  所以，我不太爱坐飞机了


Well, it still more or less means 'not anymore', because of the '了'.  '了' here also somewhat implies 'after some incident', similar to '已经'. Ex:


  去年空难之后，我就不太爱坐飞机了


So if you want to state 'I really don't like taking planes due to some reason.', then for example:  


  我有幽闭恐惧症，所以我不太爱坐飞机


would probably translate to 'I always have claustrophobia, so I don't like taking planes.'

but


  我有幽闭恐惧症，所以我不太爱坐飞机了


somewhat implies 'I recently got claustrophobia, so now I don't like taking planes.'