Using the modified AIAA style:

1. Copy modified file aiaa.bst into path 'C:\Program Files\MiKTeX 2.9\bibtex\bst\aiaa' (or equivalent) and overwrite original file (be sure to createe a backup first).

2. Implement the packages 'url' and 'doi' into the master file of your thesis:
    \usepackage{url}
    \usepackage{doi}.

3. Modify your bibliography (.bib) file in the following manner:
Instead of 'url = {http://www.url.de}', use 'url = {\url{http://www.url.de}}' to create an active hyperlink in the resulting PDF file. Proceed in the same manner for DOI links, e.g.
'doi={\doi{10.2514/6.1997-3074}}' instead of 'doi={10.2514/6.1997-3074}'. 