From a purely business point of view, with Tunisia and also Greece in economic turmoil, these are two leisure markets served by primarily low cost carriers from the UK and also holiday companies in Germany, Ireland and Scandinavia etc.
If carriers pull out from these two markets, it'll drive airfares down elsewhere as assets are utilised even more in their core markets - more secure business environments. This will have an impact on the smaller carriers.
Sad state of affairs - tragic set of events yesterday.