Packing gear, I check on the airlines website to see what is allowed and whats not, they will usually have changes on any weights they allow you to carry and item list. Also, I have traveled with a small dive knife hooked to my BCD in my checked luggage, I did not have a problem but my roommates knife was confiscated by security before we had left the states. If you plan of taking your lights for night diving, take the batteries out and have them in a separate plastic bag for travel. It makes it easier going through security. The item that I take as a carry on also gets me stop and thats my camera. When they try to x-ray it look like a black box and they can not see in it. It's the price you pay to take pictures. Have fun, I am jealous.
Scuba Mama