How do disconnect battery cable(s) at airport...

For the one trip I would just disconnect the negative cables from both batteries. But for the long term, you need to find out the problem. Two batteries should last much longer. Retired now, but when working I could leave my F350 at the airport for two weeks and it started just like normal when I returned.

Or if you truck is at home while you are gone, just put a trickle charger on it.