Re: 1940 Ship compass transport
Be aware that the cargo hold might not be pressuried and at 30,000ft any dissolved air in the compass fluid will "boil" out leaving a bubble in the fluid when you next see it.
The aircraft cabin
is normally pressuried to the equivalent of 8,000ft but they might not let you take as cabin
However some cargo holds are pressuried so it might pay to check with your chosen airline.
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence