So tomorrow looks like ATC hell at LaGuardia given the likelihood of thunderstorms. We're on the 4:15pm MKE-LGA which today has a 3 hour delay (and tomorrow's storms look worse). The next-earlier flight is scheduled at 11:35am, and getting on that one would be good.

Of course there's no free earlier-flight standby on Southwest (you pay the fare difference) unless there's a significant delay. Based on the collective FT experience with ATC hell days...

(a) If our 4:15pm flight already has a big posted ATC delay by late tomorrow morning are odds good they'd allow us on the 11:35am? Or is that just too far away?

(b) If LGA has an ATC delay program tomorrow but our 4:15pm flight still does not yet have a posted ATC delay by 11:35am is there any chance they'd be willing to put us on the earlier one based on the ATC delay program?

(c) If both flights get big ATC delays and the early one is still there by the time we get to the airport (open seats and not boarded yet) might they allow us on the earlier flight even thought that earlier flight was scheduled to leave hours earlier?

Obviously there's a certain amount of YMMV depending on the agent and situation. And of course we cant' get on a full flight, they won't let us aboard a flight already boarded and buttoned up, etc. But ATC delays for a day like tomorrow are as predictable as the sun rise and I wonder if anyone has experience to share on this topic when ATC hell is the in play.