Are your boys babies? I think it's good to take young children
on trips as a way to educate them and teach them how to behave
in stressful public situations, such as flying. I also think
that little babies are probably better off at home and should
only be subjected to the diseases and toxicity of flying when it
is unavoidable. Obviously, most little infants are not that
psyched to be on a crowded, long or delayed flight, just as most
adults do not like these conditions. Moreover, I'm pretty sure
that tiny babies do not get much from sightseeing, etc. but can
be stimulated and exposed to small travel excursions close to 
home where the parent has more control over the childs well being.