I just oticed that flight DL1972 from Austin to JFK was diverted to San Antonio today. Looking at the log on flightstats it looks like the decision to divert was made prior to takeoff with the flight then continuing to JFK almost immediately.

What would cause a situation like this to occur?

Just looked on flightstats.com and it looks like an earlier flight from San Antonio to JFK was cancelled. Maybe a diversion to pick up some passengers?

It's called a flagstop, to pick up passengers off of a cancelled flight. Only works if both flights are lightly booked so they can accommodate everyone

UA658, DEN->IAD, was diverted to Tulsa last night too, to drop some passengers who's DEN->TUL flight was cancelled. Only delayed us about an hour, but it felt very strange.

It can also happen if they know they'll need fuel along the way or for a couple other reasons.

I've experienced this...for example, we were diverted from MIA-DCA to MIA-IAD b/c of rain meaning we couldn't use the short runway and runway construction on the long runway at the time of our (very) late arrival.

So ....... Do you get credit for the extra segment?

The all-time classic of this type of situation occured some years ago, hopping all around Britain. It would be the equivalent of Austin to JFK being diverted via Seattle to pick up passengers headed for LAX !

http://www.flyertalk.com/forum/377831-post7.html

Not quite. England/Scotland is about 500 miles from north to south. Austin to Seattle is 2000 miles.

Doesn't a flagstop mean that a train or long-distance bus stops only upon demand?

Had it happen once between MEM and DTW. Very hot in MEM, full/heavy DC-9 and lots of thunderstorms enroute. After pushback while waiting for the long runway to open, the captain came on to say that because of the extra fuel needed to fly around storms, we would have to refuel in GRR. There were soem very annoyed people who were connecting in DTW to get to GRR, but they were not going to let them off - only refuel.

We did snake through some massively tall thunderstorm clouds. He announced approach into GRR so the cabin was prepared for landing. I looked out the window a few minutes later and saw DTW passing to the right. Apparently we had enough fuel to make it and a landing slot opened, so they un-diverted to DTW.

That's another meaning of the word. I know the Alaska Railroad used to do (and possibly still does) flagstops; very convenient for hikers/hunters in the wilderness!

Amtrak does this for a few stations on some trains (e.g. the Cardinal).

AA DFW-SFO became DFW-SJC before we even boarded. It actually worked really well for me as I live a few minutes away from SJC airport but for most passengers it was a total inconvenience. They offloaded everyone's luggage in SJC, arranged for two coach shuttles to take people to SFO.

No reason for this change was ever provided nor were any apologies offered. Very odd.

Sometimes they do it if they know the heads winds are going to be strong e.g. Westbound 757's from Europe they will pre-schedue a diversion to top off the tanks.