D-rob raises the point of altitude ... I can't quote chapter and verse of scientific data and fact, but will tell you that due to prior (unhappy) experience, I will not let my travel humi go in the check-in luggage ... without considering the rough treatment accorded to check-in baggage, I'll tell you that I think that since the luggage compartment is very cold and unpressurized, it's highly detrimental to cigars, even on a fairly short flight ...
It's really this simple:
* Put your lighter/cutter(s) in your check-in baggage ... although you MIGHT be able to carry them on, you might not. Why take a chance ?
* Put your cigars in a carry-on ... doing so assures you that the care, temperature and air pressure will be in favor of their being smokeable at the other end