Earlier this year, an Airbus A321 aircraft burned on the ground in Korea due to a lithium battery power bank problem.
Thankfully, there were no casualties before takeoff.
Since then, the rules have been changed to carry on only 5 lithium batteries on board at the airport in Korea.
Not long ago, I boarded an aircraft and my strobe battery was ni-mh battery, not lithium, so I was able to get through the checkpoint safely. Of course I was on the plane with a lithium battery, such as focus light, light batteries for nightdiving, etc.
Recently, Hong Kong Airlines also caught fire due to a lithium battery problem.
Perhaps it will be more difficult to fly with lithium batteries in the early future.
FYI I'm not a Retra user. I'm an inon user, but I'm seriously considering upgrading to a retra pro max that uses a ni-mh battery.
I will use a ni-mh battery powered strobe in the near future for lithium aviation regulations.