@ 115 Greg: Funny you should mention flying tanks. That is exactly what the Soviet Union considered helicopters. They reasoned that a helicopter more closely resembled a tank than it did a fighter jet, since tanks and helicopters can seize and hold terrain, whereas fighters can only fly over it and bomb it. Back in the day, Libya bought many attack helicopters from the former Soviet Union. Consequently, helicopters must be grounded, as well.
More to the point, though, in order to enforce the no-fly zone, UN aircraft must be able to fly over Libyan terrain to identify and shoot down aircraft. To do this, they must not be constantly under attack by Libyan ground-based anti-aircraft defenses. I would bet they had appropriate wording in the resolution to allow suppression of enemy air defenses, which would include disruption and destruction – accomplished by hitting them with bombs and missiles. This would be the only way they could police a no-fly zone.