There are no laws prohibiting transportation of Gold via airplane, domestically, as it presents no threat to the plane or passengers.

Are you talking about on your person, as checked baggage, or air freight? Domestic or international? What do you mean by "large ammounts". Most countries have a limit on the amount of cash or cash equivalents (I imagine this would apply)you can carry. Also, you have the normal weight restrictions. So, at today's prices, I would think that more than about 10 oz. (plus any nominal amount of cash you're carrying) would probably be the international limit-and I don't consider 10 oz. to be a large quantity.

No problem carrying it on a domestic flight in the US... though expect to attract some attention at Security. Not that it's dangerous or contraband, but it's presence will become known to Security and anyone else around who's paying attention, so it's kind of like waving a lot of cash around. You're basically advertising to be robbed. If you're travelling internationally, certain countries prohibit taking gold out of the country, even if it's "yours" (most governments with progressive tax systems and view all citizen wealth as the government's, but the government just graciously allows you to use some of their money). If you're carrying it into a country where corruption at all levels of the bureaucracy is common-place, don't be surprised if it's all confiscated on the basis of some supposed law. (Flying 1st Class with an entourage of lackeys will protect you from this, but if you're an obvious nobody expect to be fleeced.) Also, a few countries straight-out prohibit private ownership of gold, and bringing it into the country could cost you all of it, and possibly a stint in prison. That being said... In theory, taking gold across most national borders (between developed nations) is as legal as taking your shaving kit, but it will draw a lot more attention from customs and probably be taxed heavily by many countries on entry, and by many on departure, and by more than a few, both ways. You need to find out what the laws are in each country, and what are the threshhold amounts that may be permitted without duties, or at what quantity/value you may require special licenses. In practice, if you're a US Citizen taking your own bullion OUT of the US, and its current value is more than $10k, expect to be detained at the airport and heavily questioned (and threatened) by the IRS... and don't be surprised if they audit you for the next 10 years. Under new US tax laws/IRS regulations, taking ANY assets out of the country is considered prima-facie evidence of tax-evasion.