Hi y'all,

I worked for AA Operations several years ago.
I was never a big AA fan, and once I wasn't employed by them, I defected all my flying to other carriers (originally CO) where I've always maintained Platinum ... so I feel my opinion isn't biased towards AA....

AA doesn't have "fake mechanicals".
I doubt anyone in the industry does. Cancelling a flight (particuarly for an airline with multiple hubs) can create more operational nightmares than it solves. And while your "faked mechanical" flight might have had a light load, as fate would have it, the flight that the plane comes back seems to usually be oversold.

Now ... having said that ....
The plane with the mechanical problem may not be your flight's aircraft.
AA (and I'm sure every carrier) will juggle aircraft assignments once a mechanical has left the airline "short" a plane. And while frequent travellers won't believe this ... airlines actually do this juggling in an attempt to inconvienece as few passengers as possible (I'll contradict myself on this in a minute).

The plane with the "mechanical" might not even be at your departure city.
The simple case being it's still in whatever city it was flying in from. But here's a hypothetical situation which Ops sees everyday...
You're flying today DFW-PHX and your flight gets cancelled due to mechanical.
Where's the broken plane ???
It was the Chicago-Washington National plane that broke down.
That ORD-DCA flight was oversold.
The ORD-Denver flight was only booked 50 pax, so it was cancelled.
From DEN, that plane (which is now going to DCA) was to have flown DEN-DFW-San Antonio-DFW
Obviously, the DEN-DFW flight is cancelled because ORD isn't going to send them the plane.
Logic would have it that the continuation of that flight (DFW-SAT) as well as the SAT-DFW return would also be cancelled. However, lady luck has struck and there's a spare plane at DFW !!
But guess where the crew for those flights are ??
They're in DEN. They overnighted there and was to have started their day today by taking the inbound aircraft from ORD and fly it DEN-DFW-SAT-DFW.
So DFW isn't short a plane, but they are short a crew due to: mechanical
Another issue going on is that due to delayed flights earlier in the month, the crew that's flying the DFW-PHX is running short on their monthly "duty" limit ... to the point that if there's any last minute delay on the DFW-PHX flight, the crew would be "illegal" for their PHX-DFW return. Thus we're running the risk of having a plane stranded in PHX. But you know what ?? That crew has enough duty time to comfortably handle a "SAT turn"
.... so....
Your DFW-PHX flight is cancelled.
The official reason in the computer will say something like: crew/eq dist
Translated: Unable to crew due to equipment distribution
The poor Gate Agents won't know the history of how this situation evolved, but that "equipment distribution" says there was a mechanical somewhere that screwed everything up, so they'll tell you "mechanical"

And we ain't done yet.
The plane that was supposed to go ORD-DEN-DFW-SAT-DFW today was put on that routing becuase it specifically had to be in DFW tonight for its "B-check" (a mechanical checkup that occurs every 3-4 days ... it'sbased on flight hours). Instead, it's going to fly ORD-DCA-ORD-Seattle. SEA isn't equipped to do B checks. Sending the plane on to SEA tonite will leave it illegal to return in the morning. So when it gets back to ORD, it's pulled offline instead to spend the night there. The whole "equipment distribution" game starts again in trying to get the SEA flight out.

But we ain't done yet.
The 3rd shift maintenance crew at ORD ended up with one more B-check to do tonight than what the schedule said they'd have. Come tomorrow morning, ORD ops will be expecting 5 aircraft coming over from the hangar to operate trips leaving in the 6:45am departure bank. But Maintenance calls at 6:00 and says only 4 of them are ready to go, the 5th plane will be brought over at 8:00am. The day hasn't even started yet and we're already feeling the effects of yesterdays mechanical.

Because cancellations have such a "ripple down" effect, the generic rule of thumb is "don't cancel". I can't think of a time (in 7 years at AA Ops) that a flight was cancelled strictly due to low passenger count (I'm not talking about no-ops .. ie: .... in July, scheduling decided that flight #101 will not operate on Dec25 due to anticipated low load). When push comes to shove and we have no choice but to cancel something, many factors will decide which flight cancels; the passenger/freight/mail loads (out & back) being one of them.

Another trick (this is where I contradict myself about inconvienicing as few folks as possible) is the "equipment move-up".
A plane on the 2:00pm departure bank is grounded.
There are no spares until 9:00pm (of the 12 MD-80s coming in to spend the nite, 3 are not coming in for B-checks so are re-assignable)
We can delay the 2:00pmish flight until 9:30 but we don't.
A plane coming in at 3:00 and due out at 4:00 is "moved up" to fly the delayed 2:00
A plane coming in at 4:30 and due out at 5:30 is moved up to fly the delayed 4:00
Etc etc until the 9:00pm "overnighter" departs at 9:30pm as the delayed 8:00pm flight.

While this disrupts a lot of passengers today by an hour or so, when you look at the "ripple effect", it really isn't that bad of a plan. A cancellation affects the operation more than most passengers could ever imagine. Delaying the 2:00pm until 9:30pm also has many issues. For one, that plane probably turns around as a 6pmish arrival back to a hub So those inbound passengers are standed somewhere. And here's DFW at 7pm with 2 planeloads of passengers mulling about due to one plane broken. Whereas delaying several planes thru the day by an hour or so allows a lot of them to make up time before turning around back to a hub (the "spoke" city turns them around as quick as possible instead of having the plane on the ground for an hour and half). They may not get back to the hub "on-time", but will get back in time for most passengers to make their connections.

Having seen "the other side", I wouldn't try to second guess the airline.

Steve