When requesting flight schedules for any flight by JAL, it returns the actual ident as JTL:
{"AirlineFlightSchedulesResult":{"next_offset":-1,"data":[{"ident":"AAL8481","actual_ident":"JAL11","departuretime":1593879000,"arrivaltime":1593926400,"origin":"KDFW","destination":"RJTT","aircrafttype":"B789","meal_service":"Business: Meal / Economy: Meal","seats_cabin_first":0,"seats_cabin_business":44,"seats_cabin_coach":151},{"ident":"AAL8481","actual_ident":"JTL11","departuretime":1593879000,"arrivaltime":1593926400,"origin":"KDFW","destination":"RJTT","aircrafttype":"B789","meal_service":"Business: Meal / Economy: Meal","seats_cabin_first":0,"seats_cabin_business":44,"seats_cabin_coach":151},{"ident":"AAL8481","actual_ident":"JTL11","departuretime":1593879000,"arrivaltime":1593926400,"origin":"KDFW","destination":"RJTT","aircrafttype":"B789","meal_service":"Business: Meal / Economy: Meal","seats_cabin_first":0,"seats_cabin_business":44,"seats_cabin_coach":151},{"ident":"AAL8481","actual_ident":"JAL11","departuretime":1593879000,"arrivaltime":1593926400,"origin":"KDFW","destination":"RJTT","aircrafttype":"B789","meal_service":"Business: Meal / Economy: Meal","seats_cabin_first":0,"seats_cabin_business":44,"seats_cabin_coach":151},{"ident":"JAL11","actual_ident":"","departuretime":1593879000,"arrivaltime":1593926400,"origin":"KDFW","destination":"RJTT","aircrafttype":"B789","meal_service":"Business: Meal / Economy: Meal","seats_cabin_first":0,"seats_cabin_business":44,"seats_cabin_coach":151},{"ident":"JTL11","actual_ident":"","departuretime":1593879000,"arrivaltime":1593926400,"origin":"KDFW","destination":"RJTT","aircrafttype":"B789","meal_service":"Business: Meal / Economy: Meal","seats_cabin_first":0,"seats_cabin_business":44,"seats_cabin_coach":151}]}}
It looks like the FlightAware database is joining all airlines on IATA ident JL, which is now used by JAL, and used to be used by JTL.
JTL is a private jet company, which is to say, they are not scheduling any of these flights.