I assume these rules apply everywhere, so have you checked out the carrying of Lithium batteries lately. It's almost not possible.
At least with medium format you can shoot a bigger aperture and use less power, which will give a faster recycling.
Flying with li-on batteries is not a problem if you do your homework. For elinchrom rangers you remove the fuses, and tape over the contacts, download the airworthy certificate from the battery testing place in Poland, download the guidelines from your airline and work out the allowance from the amp hour rating and include the instruction manual with a post it note at the right page with flying info. This is all folded neatly and secured with a rubber band round the battery in your hand luggage. Never had an issue by doing things properly and being able to show customs/security the right paperwork.