I’m sure this has been discussed before, but I thought I just include my experience in activating SOTA on a recent trip by aircraft. There are really only two issues - the squid pole and the batteries.
For the squid pole I made a transit case out of 40mm PVC pipe with a screwed joiner. This reduces the possibility of your lovely squid pole being smashed to pieces in transit, but it does mean you have the hassle (not much) of having to lodge it at special baggage.
Spare batteries, i.e. those that are not contained within equipment with an on/off switch, must be carried in carry on baggage. I think you are allowed up to 100Wh without any issues. My battery is a 63Wh LiFePO, so there were no issues. Anything over 160Wh is not permitted. The battery terminals must be insulated. It seemed important that the battery was less than 15 volts - don’t know why. You must tick yes to Dangerous Goods, and have it inspected at the check-in desk.
I have a haversack with my portable kit, so I just carried that as my carry-on. Going through security expect a detailed inspection of your carry-on - the X-ray looks pretty interesting. Once I said “portable radio” I was sent on my way.
I activated VK4/SE-059 & VK4/SE-094 yesterday. WX was bad so I was lucky to get the 2 activations in. Thank you to all the chasers. Apologies for the APRS debacle - beaconing was turned off. Drat.