Apparently the most effective means to stop terrorists doesn't seem to be increased airline security, or increased immigration restrictions.
What does work to stop terrorism seems to be committed decent individuals defending their lives and not allowing fear to get the best of them.
The irony here is of course that governments will no doubt react to this latest attack by further restricting the freedoms of their citizens in the name of improving security.
Airlines should be able to place whatever restrictions they wish as passengers are not forced to buy tickets from them. The problem I have is the ridiculous restrictions the state has placed on immigration, border controls, and free trade that I do not believe improve security against terrorists attacks ever since 9/11.