I watched something that I found interesting last night (7/19/16). We had a storm pass through the St. Louis, MO area. It didn’t seem like a particularly bad storm but I guess I was wrong. I happened to be listening to LiveATC on my iPhone and at the same time checked out FlightAware.
I heard American Airlines 2371 calling in asking about the storm moving through the area and then watched him deviate. I didn’t actually hear him talk about it but, he may have been on a different frequency than I was listening to on LiveATC.
At first I thought he might just be making a turn and then a hold but he actually flew to KMCI which had to be his alternate. Then at about 10:30 he flew back to STL from MCI which I really didn’t expect. I guess AAL really needed that plane at STL and didn’t want to leave those passengers in Kansas City.
flightaware.com/live/flight/AAL2 … /KDFW/KMCI
“I guess AAL really needed that plane at STL and didn’t want to leave those passengers in Kansas City.”
Those may be separate, unrelated issues. The first may be the operant issue. 
I slept right thru that storm but yes AAL needs the airplane and likely the crew as well in STL to cover the downline flying on it, if they can also carry the PAX that’s an added bonus.
I’m only assuming they carried the PAX back to STL some 90 minutes later. There is no obvious way to tell.
It’s surely dependent on duty time as well so the flight crew would have the 90 minute layover plus the 45 minute flight plus whatever cleanup time is required after a flight for a flight crew to close out a flight.
I saw the same thing happening again last night. I watched 3 different flights, one from PHX, 1 from LAX, and 1 from BJX all fly holds near KMDW as an ugly storm was brewing. All of them eventually diverted to KSTL.
I didn’t look to see if they later went on up to MDW as in the case last night, the WX continued on a southerly track for the rest of the night.
