Traveling on an airline with scuba gear can be a divided challenge, where-as traveling by car is so much easier. If you have traveled with a scuba shop, then they will brief you on what to put into carry-on and what to put into your check-in luggage. Basically anything that can be an issue (like your knife or scissors,) should just be packed into your check-in luggage. Heavy items and expensive treasures (like your regulators and dive computers,) should be cradled in your arms and carried-on into that safe overhead compartment on the plane. As to (1) what to bring on the dive trip, (2) how to pack for safety that is another subject.
Personally, I have been lucky because I live not far from my local dive shop, and I visit them as often as possible. Sometimes just stopping by to share a cup of coffee. Life is beautiful. Anyway, have fun on your next trip by planning ahead of departure time. It takes me two attempts before my luggage is ready.