Shares in All Nippon Airways and battery maker GS Yuasa surged on Thursday after a report that US and Japanese regulators were preparing to give the green light to the resumption of Dreamliner flights.
Japan's Nikkei business daily said aviation safety bosses in both countries could lift the grounding order on the Boeing 787, which has been parked up at around the world since January following incidents involving its batteries.
ANA and its rival Japan Airlines (JAL) have invested heavily in the next-generation plane, and its grounding has played havoc with their schedules, forcing the cancellation of thousands of flights.
GS Yuasa, the company that makes the battery at the centre of the safety probe, saw its Tokyo-listed stocks rocket more than 11 percent at one point, before finishing the morning up 7.57 percent at 412 yen.
Shares in ANA climbed 5.07 percent to 207 yen at one point before easing to 205 yen, a gain of 4.06 percent. JAL finished the morning 0.23 percent higher at 4,230 yen, after surging 1.90 percent at one point.
All of the 50 Boeing 787 planes in service around the world were grounded in mid-January after a series of overheating problems with the cutting-edge aircraft's lithium-ion battery system.
The action came after a battery fire on a parked JAL 787 at Boston's Logan International Airport and an incident in which fumes from a battery forced the emergency landing of an ANA-operated plane in Japan.
The Nikkei said the US Federal Aviation Administration has notified Japanese officials of its intention to approve the aircraft for flight in light of the measures manufacturer Boeing is taking.
Japan's Transportation Ministry is expected to lift its own ban once the FAA makes an official announcement, the Nikkei said. The paper did not identify its sources.
In the United States, United Airlines may start flying Dreamliners as soon as late May, it said.
Among Japanese carriers ANA is looking to bring back the Dreamliner for domestic service on June 1 and JAL, which flies the Dreamliner only on international routes, plans to resume in June, it said.
Japanese officials privy to the issue were not immediately available for comment on the report, while spokesmen at ANA and JAL said they could not confirm it, adding both airlines were waiting regulators' approval.