I’m a user of flightaware.com in Japan.
It is very useful and I love it, but I can’t search some airframes registered in Japan.
For example, there is a jetliner JA8988 (A Boeing 767-300 MSN 29863 delifered for JAL), who is still flying today.
When I searched for JA8988 in Flight/Tail#, the following message was shown:
“FlightAware couldn’t find flight tracking data for BON8988 just yet.”
Unfortunately, LIVE FLIGHT TRACKER seems to mistake JA for the two letter code of airlines, i.e., Air Bosna (B&H Airlines) and 8988 for some flight number.
Let me tell that there are other jetliners with registration JAxxxx in Japan, and I’d like the system to be corrected.
For airline flights you need to know the flight number, not tail number. For example: JAL1
We now have tail number data for a number of airlines (Continental, United, Singapore, Air Canada, etc) but I don’t know if JAL is one of them.
If we do have any Japanese tails for airlines, I’ll get the rewriting of that IATA code fixed.
Thank you, everyone 
What I wanted to do was to search for particular aircrafts by their tail number.
As mduell indicated, tail number data for JAL seem to be unavailable (I tried other tail numbers but I couldn’t one of them).
In contrast, I think you may have tail number data for another Japanese largest carrier, ANA (All Nippon Airways) because the aircraft JA601A, a Boeing 767-300 jetliner for ANA, can be found certainly.
Note that, however, JA8971, a similar B763 for ANA, can’t be found.
Taking the behavior of search system into accounts, I’d like you to have the problems fixed.
I have the same problem when searching for japanese airplanes. I think, the problem is that JA is the iata code for BH airlines and the flightaware script is then looking for a BH airlines flight instead of the aircraft with the JAxxxx registration, for example JA8257. Since for example JA601A is clearly not a flight number, you find the airplane.
Maybe you should have 2 search fields, one for the flight number and one for the registration?
Does the interface need tail or registration #? Also, is there a specific list of which airlines’ aircraft are tracked? I’m specifically interested in Jazz aircraft (flown for Air Canada) as I noticed most of the regular Air Canada fleet appears but hardly any of Jazz’s aircraft (mostly CRJs) seem to be in the system.