I am in favour. It should be done on several levels i.e Intelligence etc but ALSO on appearance. If a group of young Asian males are travelling together then they should expect closer scrutiny than a bunch of elderly females on a SAGA holiday.
Mind you, I find it ironic that we are panicking about this one aspect yet airlines are still happy to shovel on groups of pi$$ed males and females to fly them to Prague/Amsterdam etc. They are a far bigger threat to safety IMHO but if you dared suggest that we made all flights alcohol free the BAA and the airlines would have a hissy fit.
Likewise, if car manufacturers were told to limit every car to a maximum of 30mph in order to cut down on the thousands of deaths on the roads every year, the same people worried about terrorism on flights would be taking to the streets demanding their rights be observed.
Crazy world.