Los Angeles to Tokyo is on sale for limited dates March to May with Air China, China Eastern and China Southern for $515 to $577 round trip. Dates can be searched through Google Flights and possibly extend into other months. Each of these airlines fly to Tokyo via a one-stop routing in China. SkyTeam airlines China Eastern and China Southern are the lowest fares on most dates, however the deep discount economy fares do not earn any frequent flyer miles in most airline programs. You can earn from 25% miles in United Mileage Plus, 50% miles in Lufthansa Miles& More and even 100% flight miles with Avianca for the 15,100 mile itinerary paying only $20 to $40 more flying Air China.
Air China Los Angeles LAX – Beijing PEK – Tokyo NRT – Beijing PEK – Los Angeles LAX
Air China Economy L class (WheretoCredit.com)
China Eastern Airlines Los Angeles LAX – Shanghai PVG – Tokyo Haneda HND – Shanghai PVG – Los Angeles LAX
China Eastern Economy Q Class (WheretoCredit.com)
China Southern is $526.96 through Expedia for these same dates transiting through Guangzhou CAN. China Southern Economy T/K class earns no miles in most SkyTeam Alliance programs.