No reason for the Israelis to invite a "true test of courage" by grounding their planes. It is a war, not a sporting contest.
As I've posted before, I'm not so interested in the morality of the war in Lebanon. That way lies endless, unresolvable debate.
I'm more interested in the practicality. Are the Israelis doing what they need to do achieve their goals? Now that I see Israel sending 10,000 troops into Lebanon, I think they are moving in the right (practical) direction.
As for Hezbollah, they seem very practical.
AFAIK they are doing exactly what they need to do to achieve their goals.