Yes, al Qaeda is growing strong, because the United States cannot smoke them out of every place where they can hide. There are too many countries in Africa and the Middle East that are willing to harbor al Qaeda. They have had some success lately, with their attacks in Libya and Kenya, which only ads to their ranks.
Although the recent war against the terrorist group Al Qaeda was mostly successful in reducing their numbers, the beliefs and zealousness of this group will cause it to keep growing as long as they still exist. Although nobody can say whether or not they are currently growing stronger, it is safe to assume that they are trying their best to bolster their forces.