I love this idea. It would help alot. No more taking off on vulched fields to check if towns down etc. Great idea 
I fail to see how having to take off is a bad thing. No one is omnipotent on a battlefield -- even less so then than now.
SmokinLoon: I think he's talking about this for the defenders, not the attackers.
I really like the idea, but I think there needs to be a semblance of ambiguity. How bout just rounding up to the nearest 5 minutes? For example, when the hangars first go down, it says 15 min til up until there are 10 min left, then 10 until 5, then 5 until they come up. I agree there should be more information for defenders, but I think you need to keep a bit of estimation in it.
Well, hangers stop burning with 5 mins till up, and you should have a rough idea of whether its been 3 or 7 minutes since drop... It's not a horrible idea per se, but I dont feel its needed either. Part of the responsibility of
both the attacker and defender is to have an idea of when things are coming up. This adds an important tactical element to the game, and makes well-planned attacks/defenses that much more effective.
As for ords/troops...if you care that much about them, resupply

I agree fog of war is a good thing, and makes the game more enjoyable.