It's well known that airlines usually permanently retire a flight number after they have a fatal crash. In fact, United took some flak last year when they accidentally reused flight numbers from the UA flights that were crashed on 9/11.

But I'm wondering, do airlines ever retire flight numbers from incidents on other airlines?

Google has a cool feature that you can Google a flight number and it will return the status. It's a quicker way to get the current info than going to the airline website or to a site like flightaware.

Well, I often fly on AA 447, so during a recent delay, I Googled "AA flight 447". The first two search results (shown right below the Google flight status) were flightaware and flightstats. But most of the rest of the page was search results with information about Air France 447, which vanished into the Atlantic in 2009, killing 228 people...