I never take weights or tanks on an airplane primarily because the dive ops supply them at no extra charge where I do most of my diving which is SE Florida and the Upper Keys. Other than that I wouldn't take them anyway because of the added weight for lead and the cost of flying with tanks. Delta quoted me $400 extra for a round-trip for the tanks and an additional baggage charge of $100 if I remember correctly. That is pretty much self-explanatory. If I insisted on using my tanks I'd send them ahead by UPS or USPS.