In light of the Christmas bombing attempt, there have been two main proposals to enhance security. The first is to enhance technological and physical security measures such as patting people down, using full body scanning devices and so on. The second is to provide more screening for people from fourteen countries that are considered high risk.
While improving security is a good idea, improvements are only worth the cost and effort when they actually are improvements.
The technological enhancements will, of course, be very expensive and raise the question of whether the security provided will be worth the cost. There is also the obvious question of whether the security systems will be in places where they are needed. After all, a clever terrorist would certainly learn where the high tech systems are located and then find airports that lack them and use those as his access point. Also, the high tech systems can be bypassed in other ways, such as taking advantage of human frailties (such as corruption). A final question is whether these systems will work as advertised without slowing air travel to a crawl. My main worry is that a lot of taxpayer money will be spent on high-tech security theater and we will not be not be significantly safer.
Of course, there is an easy way to be much safer: require everyone to wear shorts and t-shirts on the plane. What was once carry-on baggage will be put into locked containers in the plane, that cannot be accessed until after the plane has landed and reached the gate. This is, of course, completely unrealistic-for now.
In regards to putting people from specific countries under greater scrutiny seems like a good idea, it does have some serious limitations. First, there are obviously more than 14 high risk countries. Second, any clever terrorist can easily bypass this by either traveling from another country or using forged document.