Japan Airlines (JAL) says it has turned around two of its Boeing 787 Dreamliner aircraft during flights due to technical problems.
On one plane one of the two anti-ice systems, which prevent ice building up around the engine, failed.
Meanwhile, an electrical glitch made six toilets unusable on another flight.
These are the latest technical issues to hit the Dreamliner, which saw the entire fleet being grounded earlier this year following battery problems.
The anti-icing system failed on a Tokyo-bound flight that took off from San Diego.
A spokesperson for JAL told the BBC that a similar issue had forced a Tokyo-to-Singapore flight to be turned back in June this year.
Meanwhile, an electrical system failure connected to the lavatories affected a flight from Moscow to Tokyo.
The failure resulted in six of the seven toilets on the plane not being able to flush.
The airline said that it was looking into the problems.
The 787 Dreamliner has suffered a series of technical and safety problems in recent months.
In January, its entire fleet was temporarily grounded. That move was prompted after a fire broke out on one of JAL's Dreamliners, and an All Nippon Airways (ANA) flight was forced to make an emergency landing because of a battery fault and a fire in one of the electrical compartments.
Though the planes have since been allowed back into the air, other issues have emerged.
In July, a fire broke out on a 787 jet operated by Ethiopian Airlines while it was parked at Heathrow airport. It was traced to the upper rear part of the plane where a locator transmitter is located.
Then in August, ANA said it had found damage to the battery wiring on two 787 locator transmitters during checks. US carrier United Airlines also found a pinched wire during an inspection of one of its six 787s.
The issues have hurt Boeing.
Earlier this week, JAL announced a $9.5bn (£5.9bn) plane deal with rival Airbus. It is the first time that it has agreed to buy Airbus planes, having preferred Boeing for many decades.
Analysts have hinted that issues with the Dreamliner may have played a role in JAL's decision.
However, despite the issues the Dreamliner is still considered to be one of the most advanced planes in the industry and continues to remain popular.
Boeing has received orders for more than 950 jets since its launch.