[Wavytone]

Personally I'd say take binoculars and leave the scope at home.

I've travelled a few times by air with scopes, no issues apart from the weight and the compromises you'll have to make with luggage, and lugging it around with you when not using it.

For many years I had a 4" Meade SCT as a travel scope for solar eclipses, it was fine on a sturdy camera tripod, and the OTA is easy as cabin luggage. Current equivalent would be one of the baby maksutovs around 90-127mm. This would be far preferable to your refractor.

There's even a C5 with tabletop mount in the IIS classifieds... perfect.

FWIW M31 is pretty close to the sun at moment ... wrong time of year to look at that.