Are you planning to check them or carry on? I've seen people carry on tubes for things like fly fishing gear that looked to exceed the carry-on size rules in terms of length. Would they fit in something like that? Unless they have too much of a pointed end that would restrict them from carry-on eligibility (i.e. look too much like a potential weapon to pass TSA approval)?

The postal box looks like a good, secure option if you're checking.