Agreed!

I’m not an aviator, but as I understand the story and how these things work, the rescue authority contacted the aircraft directly, or possibly asked air traffic control to do so. The flight crew, having been notified, decided on their own that they could help without hazarding the aircraft.

What I don’t know is what airlines might have policies about this and what they are.

Only other time heard passenger planes been told to alter their normal routine was during the Iranian Embassy Siege.

The owner (British Airports Authority) of Heathrow airport was told to get aircraft to fly over the embassy at a lower altitude than normal. Just to create some noise cover.

Me, too, but two airliners from different airlines rerouted in this case - an Air New Zealand Airbus 320 in addition to the Air Canada Boeing 777.

Here are a few of the (many) news stories on the incident, and a few quotes from them:

"An AMSA spokeswoman said it was unusual for commercial aircraft to be called in to assist in a search and rescue effort.

"It's not common, but that's not because we try to avoid doing it," she told the Australian Associated Press. "It's because the nature of the incidents that we have aren't necessarily so remote that we can only rely on the commercial airlines."

https://www.cbc.ca/news/world/air-canada-flight-helps-locate-sailor-off-australian-coast-1.1146862

"Later, an Air New Zealand Airbus 320 en route to Sydney from Auckland was also diverted before an Australian rescue plane arrived and dropped a life raft and satellite phone down to the stranded seaman."

https://www.bbc.com/news/world-us-canada-19970274

{From the Associated Press:}
“The crew borrowed binoculars from customers and also engaged those sitting on the right hand side of the aircraft to help look. As our aircraft flew over the area at 4,000 feet, a reflection from a mirror shining upwards was spotted and the crew saw the yacht in question, de-masted with a person standing _ which was confirmed by a number of passengers."

https://www.cnbc.com/2012/10/17/air-canada-helps-find-troubled-yacht-off-australia.html

https://www.cnn.com/2012/10/18/travel/australia-yacht-rescue/index.html

https://www.ctvnews.ca/world/air-canada-...tralia-1.997459

https://www.cnbc.com/2012/10/17/air-canada-helps-find-troubled-yacht-off-australia.html

A signal mirror enabled this rescue - but don't count on getting this lucky ...

The fisherman was rescued when the signal mirror suspended from his neck reflected light to his rescuers ... at night! (1:30 AM)

Rescuer quote: “We were under night vision goggles, looking around and we saw a flash of light from his signal mirror that he happened to have around his neck,”

The moon was 88% full that night, so the reflection off the mirror may have been the moon.

I've used a signal mirror to deliberately flash moonlight but this is the first account I recall where an accidental moon reflection was credited.

Full article here: Missing Fisherman Rescued by HSM-37 Helicopter Team in Oahu Waters

The above is the only report I found that mentioned the signal mirror, but here are other reports on the incident:

Survivor located at 1:30AM
US Navy Press Release with video
US Coast Guard News Release
Rescuer Hometown Paper Coverage
US Navy Community Outreach
USCG Bulletin when search in progress

[ UPDATE: This article mentions the mirror, and in the interview recording, the airman mentions the mirror as well:
Article with recorded interview of airman
Here's another article mentioning the mirror
Article about rescue swimmer ]

Wow! I hope he bought a lottery ticket when he got home!

It may not be wise to count on it. It surely is worth a shot to keep the mirror suspended as it might help.
Accidental reflection may be seen. By a strange coincindence I recently watched an episode of "SAS - Survival Secrets". A quote from that was "a guy with a wrist watch can compromomise the entire mission". Those blokes do not want to be found. So for our purposes a tuna can sized watch may help to be found too.
The incident also shows how good those resquers are.

Had a recent idea, was to make a phone case with a signal mirror built in.

Could have the mirror facing the back of the phone to protect it. Just take the case off to use.

While you are at it, make space for a couple of matches, perhaps a ferro rod, tinder etc, but keep it tiny and flat.

Voila! The Ren Rescue Case!

Yes, space for UCO stormproof refill perhaps

https://www.ucogear.com/firestarting/matches/survival-stormproof-matches-10-pack-in-bag-mt--sv--bulk

There are small ferrorods made to replace the toothpick in Swiss Army knives.

https://tortoisegear.com/product-category/all-products/firefly-fire-starters/

Small but apparently work.

As for flat tinders

There is the old Hammaro fire lighting paper

https://www.lightingpaper.com/